tor

TOR(1)                            Tor Manual                            TOR(1)



NAME
       tor - The second-generation onion router

SYNOPSIS
       tor [OPTION value]...

DESCRIPTION
       Tor is a connection-oriented anonymizing communication service. Users
       choose a source-routed path through a set of nodes, and negotiate a
       "virtual circuit" through the network, in which each node knows its
       predecessor and successor, but no others. Traffic flowing down the
       circuit is unwrapped by a symmetric key at each node, which reveals the
       downstream node.

       Basically, Tor provides a distributed network of servers or relays
       ("onion routers"). Users bounce their TCP streams — web traffic, ftp,
       ssh, etc. — around the network, and recipients, observers, and even the
       relays themselves have difficulty tracking the source of the stream.

       By default, tor will act as a client only. To help the network by
       providing bandwidth as a relay, change the ORPort configuration option
       — see below. Please also consult the documentation on the Tor Project’s
       website.

COMMAND-LINE OPTIONS
       -h, -help
           Display a short help message and exit.

       -f FILE
           Specify a new configuration file to contain further Tor
           configuration options OR pass - to make Tor read its configuration
           from standard input. (Default: /etc/tor/torrc, or $HOME/.torrc if
           that file is not found)

       --allow-missing-torrc
           Do not require that configuration file specified by -f exist if
           default torrc can be accessed.

       --defaults-torrc FILE
           Specify a file in which to find default values for Tor options. The
           contents of this file are overridden by those in the regular
           configuration file, and by those on the command line. (Default:
           /etc/tor/torrc-defaults.)

       --ignore-missing-torrc
           Specifies that Tor should treat a missing torrc file as though it
           were empty. Ordinarily, Tor does this for missing default torrc
           files, but not for those specified on the command line.

       --hash-password PASSWORD
           Generates a hashed password for control port access.

       --list-fingerprint
           Generate your keys and output your nickname and fingerprint.

       --verify-config
           Verify the configuration file is valid.

       --service install [--options command-line options]
           Install an instance of Tor as a Windows service, with the provided
           command-line options. Current instructions can be found at
           https://www.torproject.org/docs/faq#NTService

       --service remove|start|stop
           Remove, start, or stop a configured Tor Windows service.

       --nt-service
           Used internally to implement a Windows service.

       --list-torrc-options
           List all valid options.

       --list-deprecated-options
           List all valid options that are scheduled to become obsolete in a
           future version. (This is a warning, not a promise.)

       --version
           Display Tor version and exit.

       --quiet|--hush
           Override the default console log. By default, Tor starts out
           logging messages at level "notice" and higher to the console. It
           stops doing so after it parses its configuration, if the
           configuration tells it to log anywhere else. You can override this
           behavior with the --hush option, which tells Tor to only send
           warnings and errors to the console, or with the --quiet option,
           which tells Tor not to log to the console at all.

       --keygen [--newpass]
           Running "tor --keygen" creates a new ed25519 master identity key
           for a relay, or only a fresh temporary signing key and certificate,
           if you already have a master key. Optionally you can encrypt the
           master identity key with a passphrase: Tor will ask you for one. If
           you don’t want to encrypt the master key, just don’t enter any
           passphrase when asked.


           The --newpass option should be used with --keygen only when you
           need to add, change, or remove a passphrase on an existing ed25519
           master identity key. You will be prompted for the old passphase (if
           any), and the new passphrase (if any).


           When generating a master key, you will probably want to use
           --DataDirectory to control where the keys and certificates will be
           stored, and --SigningKeyLifetime to control their lifetimes. Their
           behavior is as documented in the server options section below. (You
           must have write access to the specified DataDirectory.)


           To use the generated files, you must copy them to the
           DataDirectory/keys directory of your Tor daemon, and make sure that
           they are owned by the user actually running the Tor daemon on your
           system.

       --passphrase-fd FILEDES
           Filedescriptor to read the passphrase from. Note that unlike with
           the tor-gencert program, the entire file contents are read and used
           as the passphrase, including any trailing newlines. Default: read
           from the terminal.

       --key-expiration [purpose]
           The purpose specifies which type of key certificate to determine
           the expiration of. The only currently recognised purpose is "sign".


           Running "tor --key-expiration sign" will attempt to find your
           signing key certificate and will output, both in the logs as well
           as to stdout, the signing key certificate’s expiration time in
           ISO-8601 format. For example, the output sent to stdout will be of
           the form: "signing-cert-expiry: 2017-07-25 08:30:15 UTC"

       Other options can be specified on the command-line in the format
       "--option value", in the format "option value", or in a configuration
       file. For instance, you can tell Tor to start listening for SOCKS
       connections on port 9999 by passing --SocksPort 9999 or SocksPort 9999
       to it on the command line, or by putting "SocksPort 9999" in the
       configuration file. You will need to quote options with spaces in them:
       if you want Tor to log all debugging messages to debug.log, you will
       probably need to say --Log debug file debug.log.

       Options on the command line override those in configuration files. See
       the next section for more information.

THE CONFIGURATION FILE FORMAT
       All configuration options in a configuration are written on a single
       line by default. They take the form of an option name and a value, or
       an option name and a quoted value (option value or option "value").
       Anything after a # character is treated as a comment. Options are
       case-insensitive. C-style escaped characters are allowed inside quoted
       values. To split one configuration entry into multiple lines, use a
       single backslash character (\) before the end of the line. Comments can
       be used in such multiline entries, but they must start at the beginning
       of a line.

       Configuration options can be imported from files or folders using the
       %include option with the value being a path. If the path is a file, the
       options from the file will be parsed as if they were written where the
       %include option is. If the path is a folder, all files on that folder
       will be parsed following lexical order. Files starting with a dot are
       ignored. Files on subfolders are ignored. The %include option can be
       used recursively.

       By default, an option on the command line overrides an option found in
       the configuration file, and an option in a configuration file overrides
       one in the defaults file.

       This rule is simple for options that take a single value, but it can
       become complicated for options that are allowed to occur more than
       once: if you specify four SocksPorts in your configuration file, and
       one more SocksPort on the command line, the option on the command line
       will replace all of the SocksPorts in the configuration file. If this
       isn’t what you want, prefix the option name with a plus sign (+), and
       it will be appended to the previous set of options instead. For
       example, setting SocksPort 9100 will use only port 9100, but setting
       +SocksPort 9100 will use ports 9100 and 9050 (because this is the
       default).

       Alternatively, you might want to remove every instance of an option in
       the configuration file, and not replace it at all: you might want to
       say on the command line that you want no SocksPorts at all. To do that,
       prefix the option name with a forward slash (/). You can use the plus
       sign (+) and the forward slash (/) in the configuration file and on the
       command line.

GENERAL OPTIONS
       BandwidthRate N
       bytes|KBytes|MBytes|GBytes|TBytes|KBits|MBits|GBits|TBits
           A token bucket limits the average incoming bandwidth usage on this
           node to the specified number of bytes per second, and the average
           outgoing bandwidth usage to that same value. If you want to run a
           relay in the public network, this needs to be at the very least 75
           KBytes for a relay (that is, 600 kbits) or 50 KBytes for a bridge
           (400 kbits) — but of course, more is better; we recommend at least
           250 KBytes (2 mbits) if possible. (Default: 1 GByte)


           Note that this option, and other bandwidth-limiting options, apply
           to TCP data only: They do not count TCP headers or DNS traffic.


           With this option, and in other options that take arguments in
           bytes, KBytes, and so on, other formats are also supported.
           Notably, "KBytes" can also be written as "kilobytes" or "kb";
           "MBytes" can be written as "megabytes" or "MB"; "kbits" can be
           written as "kilobits"; and so forth. Tor also accepts "byte" and
           "bit" in the singular. The prefixes "tera" and "T" are also
           recognized. If no units are given, we default to bytes. To avoid
           confusion, we recommend writing "bytes" or "bits" explicitly, since
           it’s easy to forget that "B" means bytes, not bits.

       BandwidthBurst N
       bytes|KBytes|MBytes|GBytes|TBytes|KBits|MBits|GBits|TBits
           Limit the maximum token bucket size (also known as the burst) to
           the given number of bytes in each direction. (Default: 1 GByte)

       MaxAdvertisedBandwidth N
       bytes|KBytes|MBytes|GBytes|TBytes|KBits|MBits|GBits|TBits
           If set, we will not advertise more than this amount of bandwidth
           for our BandwidthRate. Server operators who want to reduce the
           number of clients who ask to build circuits through them (since
           this is proportional to advertised bandwidth rate) can thus reduce
           the CPU demands on their server without impacting network
           performance.

       RelayBandwidthRate N
       bytes|KBytes|MBytes|GBytes|TBytes|KBits|MBits|GBits|TBits
           If not 0, a separate token bucket limits the average incoming
           bandwidth usage for _relayed traffic_ on this node to the specified
           number of bytes per second, and the average outgoing bandwidth
           usage to that same value. Relayed traffic currently is calculated
           to include answers to directory requests, but that may change in
           future versions. They do not include directory fetches by the relay
           (from authority or other relays), because that is considered
           "client" activity. (Default: 0)

       RelayBandwidthBurst N
       bytes|KBytes|MBytes|GBytes|TBytes|KBits|MBits|GBits|TBits
           If not 0, limit the maximum token bucket size (also known as the
           burst) for _relayed traffic_ to the given number of bytes in each
           direction. They do not include directory fetches by the relay (from
           authority or other relays), because that is considered "client"
           activity. (Default: 0)

       PerConnBWRate N
       bytes|KBytes|MBytes|GBytes|TBytes|KBits|MBits|GBits|TBits
           If this option is set manually, or via the "perconnbwrate"
           consensus field, Tor will use it for separate rate limiting for
           each connection from a non-relay. (Default: 0)

       PerConnBWBurst N
       bytes|KBytes|MBytes|GBytes|TBytes|KBits|MBits|GBits|TBits
           If this option is set manually, or via the "perconnbwburst"
           consensus field, Tor will use it for separate rate limiting for
           each connection from a non-relay. (Default: 0)

       ClientTransportPlugin transport socks4|socks5 IP:PORT,
       ClientTransportPlugin transport exec path-to-binary [options]
           In its first form, when set along with a corresponding Bridge line,
           the Tor client forwards its traffic to a SOCKS-speaking proxy on
           "IP:PORT". (IPv4 addresses should written as-is; IPv6 addresses
           should be wrapped in square brackets.) It’s the duty of that proxy
           to properly forward the traffic to the bridge.


           In its second form, when set along with a corresponding Bridge
           line, the Tor client launches the pluggable transport proxy
           executable in path-to-binary using options as its command-line
           options, and forwards its traffic to it. It’s the duty of that
           proxy to properly forward the traffic to the bridge.

       ServerTransportPlugin transport exec path-to-binary [options]
           The Tor relay launches the pluggable transport proxy in
           path-to-binary using options as its command-line options, and
           expects to receive proxied client traffic from it.

       ServerTransportListenAddr transport IP:PORT
           When this option is set, Tor will suggest IP:PORT as the listening
           address of any pluggable transport proxy that tries to launch
           transport. (IPv4 addresses should written as-is; IPv6 addresses
           should be wrapped in square brackets.)

       ServerTransportOptions transport k=v k=v ...
           When this option is set, Tor will pass the k=v parameters to any
           pluggable transport proxy that tries to launch transport.

           (Example: ServerTransportOptions obfs45 shared-secret=bridgepasswd
           cache=/var/lib/tor/cache)

       ExtORPort [address:]port|auto
           Open this port to listen for Extended ORPort connections from your
           pluggable transports.

       ExtORPortCookieAuthFile Path
           If set, this option overrides the default location and file name
           for the Extended ORPort’s cookie file — the cookie file is needed
           for pluggable transports to communicate through the Extended
           ORPort.

       ExtORPortCookieAuthFileGroupReadable 0|1
           If this option is set to 0, don’t allow the filesystem group to
           read the Extended OR Port cookie file. If the option is set to 1,
           make the cookie file readable by the default GID. [Making the file
           readable by other groups is not yet implemented; let us know if you
           need this for some reason.] (Default: 0)

       ConnLimit NUM
           The minimum number of file descriptors that must be available to
           the Tor process before it will start. Tor will ask the OS for as
           many file descriptors as the OS will allow (you can find this by
           "ulimit -H -n"). If this number is less than ConnLimit, then Tor
           will refuse to start.


           Tor relays need thousands of sockets, to connect to every other
           relay. If you are running a private bridge, you can reduce the
           number of sockets that Tor uses. For example, to limit Tor to 500
           sockets, run "ulimit -n 500" in a shell. Then start tor in the same
           shell, with ConnLimit 500. You may also need to set DisableOOSCheck
           0.


           Unless you have severely limited sockets, you probably don’t need
           to adjust ConnLimit itself. It has no effect on Windows, since that
           platform lacks getrlimit(). (Default: 1000)

       DisableNetwork 0|1
           When this option is set, we don’t listen for or accept any
           connections other than controller connections, and we close (and
           don’t reattempt) any outbound connections. Controllers sometimes
           use this option to avoid using the network until Tor is fully
           configured. Tor will make still certain network-related calls (like
           DNS lookups) as a part of its configuration process, even if
           DisableNetwork is set. (Default: 0)

       ConstrainedSockets 0|1
           If set, Tor will tell the kernel to attempt to shrink the buffers
           for all sockets to the size specified in ConstrainedSockSize. This
           is useful for virtual servers and other environments where system
           level TCP buffers may be limited. If you’re on a virtual server,
           and you encounter the "Error creating network socket: No buffer
           space available" message, you are likely experiencing this problem.


           The preferred solution is to have the admin increase the buffer
           pool for the host itself via /proc/sys/net/ipv4/tcp_mem or
           equivalent facility; this configuration option is a second-resort.


           The DirPort option should also not be used if TCP buffers are
           scarce. The cached directory requests consume additional sockets
           which exacerbates the problem.


           You should not enable this feature unless you encounter the "no
           buffer space available" issue. Reducing the TCP buffers affects
           window size for the TCP stream and will reduce throughput in
           proportion to round trip time on long paths. (Default: 0)

       ConstrainedSockSize N bytes|KBytes
           When ConstrainedSockets is enabled the receive and transmit buffers
           for all sockets will be set to this limit. Must be a value between
           2048 and 262144, in 1024 byte increments. Default of 8192 is
           recommended.

       ControlPort PORT|unix:path|auto [flags]
           If set, Tor will accept connections on this port and allow those
           connections to control the Tor process using the Tor Control
           Protocol (described in control-spec.txt in torspec). Note: unless
           you also specify one or more of HashedControlPassword or
           CookieAuthentication, setting this option will cause Tor to allow
           any process on the local host to control it. (Setting both
           authentication methods means either method is sufficient to
           authenticate to Tor.) This option is required for many Tor
           controllers; most use the value of 9051. If a unix domain socket is
           used, you may quote the path using standard C escape sequences. Set
           it to "auto" to have Tor pick a port for you. (Default: 0)


           Recognized flags are...

           GroupWritable
               Unix domain sockets only: makes the socket get created as
               group-writable.

           WorldWritable
               Unix domain sockets only: makes the socket get created as
               world-writable.

           RelaxDirModeCheck
               Unix domain sockets only: Do not insist that the directory that
               holds the socket be read-restricted.

       ControlSocket Path
           Like ControlPort, but listens on a Unix domain socket, rather than
           a TCP socket.  0 disables ControlSocket. (Unix and Unix-like
           systems only.) (Default: 0)

       ControlSocketsGroupWritable 0|1
           If this option is set to 0, don’t allow the filesystem group to
           read and write unix sockets (e.g. ControlSocket). If the option is
           set to 1, make the control socket readable and writable by the
           default GID. (Default: 0)

       HashedControlPassword hashed_password
           Allow connections on the control port if they present the password
           whose one-way hash is hashed_password. You can compute the hash of
           a password by running "tor --hash-password password". You can
           provide several acceptable passwords by using more than one
           HashedControlPassword line.

       CookieAuthentication 0|1
           If this option is set to 1, allow connections on the control port
           when the connecting process knows the contents of a file named
           "control_auth_cookie", which Tor will create in its data directory.
           This authentication method should only be used on systems with good
           filesystem security. (Default: 0)

       CookieAuthFile Path
           If set, this option overrides the default location and file name
           for Tor’s cookie file. (See CookieAuthentication above.)

       CookieAuthFileGroupReadable 0|1
           If this option is set to 0, don’t allow the filesystem group to
           read the cookie file. If the option is set to 1, make the cookie
           file readable by the default GID. [Making the file readable by
           other groups is not yet implemented; let us know if you need this
           for some reason.] (Default: 0)

       ControlPortWriteToFile Path
           If set, Tor writes the address and port of any control port it
           opens to this address. Usable by controllers to learn the actual
           control port when ControlPort is set to "auto".

       ControlPortFileGroupReadable 0|1
           If this option is set to 0, don’t allow the filesystem group to
           read the control port file. If the option is set to 1, make the
           control port file readable by the default GID. (Default: 0)

       DataDirectory DIR
           Store working data in DIR. Can not be changed while tor is running.
           (Default: ~/.tor if your home directory is not /; otherwise,
           /var/lib/tor. On Windows, the default is your ApplicationData
           folder.)

       DataDirectoryGroupReadable 0|1
           If this option is set to 0, don’t allow the filesystem group to
           read the DataDirectory. If the option is set to 1, make the
           DataDirectory readable by the default GID. (Default: 0)

       CacheDirectory DIR
           Store cached directory data in DIR. Can not be changed while tor is
           running. (Default: uses the value of DataDirectory.)

       CacheDirectoryGroupReadable 0|1|auto
           If this option is set to 0, don’t allow the filesystem group to
           read the CacheDirectory. If the option is set to 1, make the
           CacheDirectory readable by the default GID. If the option is
           "auto", then we use the setting for DataDirectoryGroupReadable when
           the CacheDirectory is the same as the DataDirectory, and 0
           otherwise. (Default: auto)

       FallbackDir ipv4address:port orport=port id=fingerprint [weight=num]
       [ipv6=[ipv6address]:orport]
           When we’re unable to connect to any directory cache for directory
           info (usually because we don’t know about any yet) we try a
           directory authority. Clients also simultaneously try a FallbackDir,
           to avoid hangs on client startup if a directory authority is down.
           Clients retry FallbackDirs more often than directory authorities,
           to reduce the load on the directory authorities. By default, the
           directory authorities are also FallbackDirs. Specifying a
           FallbackDir replaces Tor’s default hard-coded FallbackDirs (if
           any). (See the DirAuthority entry for an explanation of each flag.)

       UseDefaultFallbackDirs 0|1
           Use Tor’s default hard-coded FallbackDirs (if any). (When a
           FallbackDir line is present, it replaces the hard-coded
           FallbackDirs, regardless of the value of UseDefaultFallbackDirs.)
           (Default: 1)

       DirAuthority [nickname] [flags] ipv4address:port fingerprint
           Use a nonstandard authoritative directory server at the provided
           address and port, with the specified key fingerprint. This option
           can be repeated many times, for multiple authoritative directory
           servers. Flags are separated by spaces, and determine what kind of
           an authority this directory is. By default, an authority is not
           authoritative for any directory style or version unless an
           appropriate flag is given. Tor will use this authority as a bridge
           authoritative directory if the "bridge" flag is set. If a flag
           "orport=port" is given, Tor will use the given port when opening
           encrypted tunnels to the dirserver. If a flag "weight=num" is
           given, then the directory server is chosen randomly with
           probability proportional to that weight (default 1.0). If a flag
           "v3ident=fp" is given, the dirserver is a v3 directory authority
           whose v3 long-term signing key has the fingerprint fp. Lastly, if
           an "ipv6=[ipv6address]:orport" flag is present, then the directory
           authority is listening for IPv6 connections on the indicated IPv6
           address and OR Port.


           Tor will contact the authority at ipv4address to download directory
           documents. The provided port value is a dirport; clients ignore
           this in favor of the specified "orport=" value. If an IPv6 ORPort
           is supplied, Tor will also download directory documents at the IPv6
           ORPort.


           If no DirAuthority line is given, Tor will use the default
           directory authorities. NOTE: this option is intended for setting up
           a private Tor network with its own directory authorities. If you
           use it, you will be distinguishable from other users, because you
           won’t believe the same authorities they do.

       DirAuthorityFallbackRate NUM
           When configured to use both directory authorities and fallback
           directories, the directory authorities also work as fallbacks. They
           are chosen with their regular weights, multiplied by this number,
           which should be 1.0 or less. The default is less than 1, to reduce
           load on authorities. (Default: 0.1)

       AlternateDirAuthority [nickname] [flags] ipv4address:port fingerprint

       AlternateBridgeAuthority [nickname] [flags] ipv4address:port
       fingerprint
           These options behave as DirAuthority, but they replace fewer of the
           default directory authorities. Using AlternateDirAuthority replaces
           the default Tor directory authorities, but leaves the default
           bridge authorities in place. Similarly, AlternateBridgeAuthority
           replaces the default bridge authority, but leaves the directory
           authorities alone.

       DisableAllSwap 0|1
           If set to 1, Tor will attempt to lock all current and future memory
           pages, so that memory cannot be paged out. Windows, OS X and
           Solaris are currently not supported. We believe that this feature
           works on modern Gnu/Linux distributions, and that it should work on
           *BSD systems (untested). This option requires that you start your
           Tor as root, and you should use the User option to properly reduce
           Tor’s privileges. Can not be changed while tor is running.
           (Default: 0)

       DisableDebuggerAttachment 0|1
           If set to 1, Tor will attempt to prevent basic debugging attachment
           attempts by other processes. This may also keep Tor from generating
           core files if it crashes. It has no impact for users who wish to
           attach if they have CAP_SYS_PTRACE or if they are root. We believe
           that this feature works on modern Gnu/Linux distributions, and that
           it may also work on *BSD systems (untested). Some modern Gnu/Linux
           systems such as Ubuntu have the kernel.yama.ptrace_scope sysctl and
           by default enable it as an attempt to limit the PTRACE scope for
           all user processes by default. This feature will attempt to limit
           the PTRACE scope for Tor specifically - it will not attempt to
           alter the system wide ptrace scope as it may not even exist. If you
           wish to attach to Tor with a debugger such as gdb or strace you
           will want to set this to 0 for the duration of your debugging.
           Normal users should leave it on. Disabling this option while Tor is
           running is prohibited. (Default: 1)

       FetchDirInfoEarly 0|1
           If set to 1, Tor will always fetch directory information like other
           directory caches, even if you don’t meet the normal criteria for
           fetching early. Normal users should leave it off. (Default: 0)

       FetchDirInfoExtraEarly 0|1
           If set to 1, Tor will fetch directory information before other
           directory caches. It will attempt to download directory information
           closer to the start of the consensus period. Normal users should
           leave it off. (Default: 0)

       FetchHidServDescriptors 0|1
           If set to 0, Tor will never fetch any hidden service descriptors
           from the rendezvous directories. This option is only useful if
           you’re using a Tor controller that handles hidden service fetches
           for you. (Default: 1)

       FetchServerDescriptors 0|1
           If set to 0, Tor will never fetch any network status summaries or
           server descriptors from the directory servers. This option is only
           useful if you’re using a Tor controller that handles directory
           fetches for you. (Default: 1)

       FetchUselessDescriptors 0|1
           If set to 1, Tor will fetch every consensus flavor, and all server
           descriptors and authority certificates referenced by those
           consensuses, except for extra info descriptors. When this option is
           1, Tor will also keep fetching descriptors, even when idle. If set
           to 0, Tor will avoid fetching useless descriptors: flavors that it
           is not using to build circuits, and authority certificates it does
           not trust. When Tor hasn’t built any application circuits, it will
           go idle, and stop fetching descriptors. This option is useful if
           you’re using a tor client with an external parser that uses a full
           consensus. This option fetches all documents except extrainfo
           descriptors, DirCache fetches and serves all documents except
           extrainfo descriptors, DownloadExtraInfo* fetches extrainfo
           documents, and serves them if DirCache is on, and
           UseMicrodescriptors changes the flavour of consensues and
           descriptors that is fetched and used for building circuits.
           (Default: 0)

       HTTPProxy host[:port]
           Tor will make all its directory requests through this host:port (or
           host:80 if port is not specified), rather than connecting directly
           to any directory servers. (DEPRECATED: As of 0.3.1.0-alpha you
           should use HTTPSProxy.)

       HTTPProxyAuthenticator username:password
           If defined, Tor will use this username:password for Basic HTTP
           proxy authentication, as in RFC 2617. This is currently the only
           form of HTTP proxy authentication that Tor supports; feel free to
           submit a patch if you want it to support others. (DEPRECATED: As of
           0.3.1.0-alpha you should use HTTPSProxyAuthenticator.)

       HTTPSProxy host[:port]
           Tor will make all its OR (SSL) connections through this host:port
           (or host:443 if port is not specified), via HTTP CONNECT rather
           than connecting directly to servers. You may want to set
           FascistFirewall to restrict the set of ports you might try to
           connect to, if your HTTPS proxy only allows connecting to certain
           ports.

       HTTPSProxyAuthenticator username:password
           If defined, Tor will use this username:password for Basic HTTPS
           proxy authentication, as in RFC 2617. This is currently the only
           form of HTTPS proxy authentication that Tor supports; feel free to
           submit a patch if you want it to support others.

       Sandbox 0|1
           If set to 1, Tor will run securely through the use of a syscall
           sandbox. Otherwise the sandbox will be disabled. The option is
           currently an experimental feature. It only works on Linux-based
           operating systems, and only when Tor has been built with the
           libseccomp library. This option can not be changed while tor is
           running.

           When the Sandbox is 1, the following options can not be changed
           when tor is running: Address ConnLimit CookieAuthFile
           DirPortFrontPage ExtORPortCookieAuthFile Logs
           ServerDNSResolvConfFile Tor must remain in client or server mode
           (some changes to ClientOnly and ORPort are not allowed).
           ClientOnionAuthDir and any files in it won’t reload on HUP signal.
           (Default: 0)

       Socks4Proxy host[:port]
           Tor will make all OR connections through the SOCKS 4 proxy at
           host:port (or host:1080 if port is not specified).

       Socks5Proxy host[:port]
           Tor will make all OR connections through the SOCKS 5 proxy at
           host:port (or host:1080 if port is not specified).

       Socks5ProxyUsername username

       Socks5ProxyPassword password
           If defined, authenticate to the SOCKS 5 server using username and
           password in accordance to RFC 1929. Both username and password must
           be between 1 and 255 characters.

       UnixSocksGroupWritable 0|1
           If this option is set to 0, don’t allow the filesystem group to
           read and write unix sockets (e.g. SocksPort unix:). If the option
           is set to 1, make the Unix socket readable and writable by the
           default GID. (Default: 0)

       KeepalivePeriod NUM
           To keep firewalls from expiring connections, send a padding
           keepalive cell every NUM seconds on open connections that are in
           use. (Default: 5 minutes)

       Log minSeverity[-maxSeverity] stderr|stdout|syslog
           Send all messages between minSeverity and maxSeverity to the
           standard output stream, the standard error stream, or to the system
           log. (The "syslog" value is only supported on Unix.) Recognized
           severity levels are debug, info, notice, warn, and err. We advise
           using "notice" in most cases, since anything more verbose may
           provide sensitive information to an attacker who obtains the logs.
           If only one severity level is given, all messages of that level or
           higher will be sent to the listed destination.

       Log minSeverity[-maxSeverity] file FILENAME
           As above, but send log messages to the listed filename. The "Log"
           option may appear more than once in a configuration file. Messages
           are sent to all the logs that match their severity level.

       Log [domain,...]minSeverity[-maxSeverity] ... file FILENAME

       Log [domain,...]minSeverity[-maxSeverity] ... stderr|stdout|syslog
           As above, but select messages by range of log severity and by a set
           of "logging domains". Each logging domain corresponds to an area of
           functionality inside Tor. You can specify any number of severity
           ranges for a single log statement, each of them prefixed by a
           comma-separated list of logging domains. You can prefix a domain
           with ~ to indicate negation, and use * to indicate "all domains".
           If you specify a severity range without a list of domains, it
           matches all domains.


           This is an advanced feature which is most useful for debugging one
           or two of Tor’s subsystems at a time.


           The currently recognized domains are: general, crypto, net, config,
           fs, protocol, mm, http, app, control, circ, rend, bug, dir,
           dirserv, or, edge, acct, hist, handshake, heartbeat, channel,
           sched, guard, consdiff, and dos. Domain names are case-insensitive.


           For example, "Log [handshake]debug [~net,~mm]info notice stdout"
           sends to stdout: all handshake messages of any severity, all
           info-and-higher messages from domains other than networking and
           memory management, and all messages of severity notice or higher.

       LogMessageDomains 0|1
           If 1, Tor includes message domains with each log message. Every log
           message currently has at least one domain; most currently have
           exactly one. This doesn’t affect controller log messages. (Default:
           0)

       MaxUnparseableDescSizeToLog N bytes|KBytes|MBytes|GBytes|TBytes
           Unparseable descriptors (e.g. for votes, consensuses, routers) are
           logged in separate files by hash, up to the specified size in
           total. Note that only files logged during the lifetime of this Tor
           process count toward the total; this is intended to be used to
           debug problems without opening live servers to resource exhaustion
           attacks. (Default: 10 MB)

       OutboundBindAddress IP
           Make all outbound connections originate from the IP address
           specified. This is only useful when you have multiple network
           interfaces, and you want all of Tor’s outgoing connections to use a
           single one. This option may be used twice, once with an IPv4
           address and once with an IPv6 address. IPv6 addresses should be
           wrapped in square brackets. This setting will be ignored for
           connections to the loopback addresses (127.0.0.0/8 and ::1), and is
           not used for DNS requests as well.

       OutboundBindAddressOR IP
           Make all outbound non-exit (relay and other) connections originate
           from the IP address specified. This option overrides
           OutboundBindAddress for the same IP version. This option may be
           used twice, once with an IPv4 address and once with an IPv6
           address. IPv6 addresses should be wrapped in square brackets. This
           setting will be ignored for connections to the loopback addresses
           (127.0.0.0/8 and ::1).

       OutboundBindAddressExit IP
           Make all outbound exit connections originate from the IP address
           specified. This option overrides OutboundBindAddress for the same
           IP version. This option may be used twice, once with an IPv4
           address and once with an IPv6 address. IPv6 addresses should be
           wrapped in square brackets. This setting will be ignored for
           connections to the loopback addresses (127.0.0.0/8 and ::1).

       PidFile FILE
           On startup, write our PID to FILE. On clean shutdown, remove FILE.
           Can not be changed while tor is running.

       ProtocolWarnings 0|1
           If 1, Tor will log with severity 'warn' various cases of other
           parties not following the Tor specification. Otherwise, they are
           logged with severity 'info'. (Default: 0)

       RunAsDaemon 0|1
           If 1, Tor forks and daemonizes to the background. This option has
           no effect on Windows; instead you should use the --service
           command-line option. Can not be changed while tor is running.
           (Default: 0)

       LogTimeGranularity NUM
           Set the resolution of timestamps in Tor’s logs to NUM milliseconds.
           NUM must be positive and either a divisor or a multiple of 1
           second. Note that this option only controls the granularity written
           by Tor to a file or console log. Tor does not (for example) "batch
           up" log messages to affect times logged by a controller, times
           attached to syslog messages, or the mtime fields on log files.
           (Default: 1 second)

       TruncateLogFile 0|1
           If 1, Tor will overwrite logs at startup and in response to a HUP
           signal, instead of appending to them. (Default: 0)

       SyslogIdentityTag tag
           When logging to syslog, adds a tag to the syslog identity such that
           log entries are marked with "Tor-tag". Can not be changed while tor
           is running. (Default: none)

       AndroidIdentityTag tag
           When logging to Android’s logging subsystem, adds a tag to the log
           identity such that log entries are marked with "Tor-tag". Can not
           be changed while tor is running. (Default: none)

       SafeLogging 0|1|relay
           Tor can scrub potentially sensitive strings from log messages (e.g.
           addresses) by replacing them with the string [scrubbed]. This way
           logs can still be useful, but they don’t leave behind personally
           identifying information about what sites a user might have visited.


           If this option is set to 0, Tor will not perform any scrubbing, if
           it is set to 1, all potentially sensitive strings are replaced. If
           it is set to relay, all log messages generated when acting as a
           relay are sanitized, but all messages generated when acting as a
           client are not. Note: Tor may not heed this option when logging at
           log levels below Notice. (Default: 1)

       User Username
           On startup, setuid to this user and setgid to their primary group.
           Can not be changed while tor is running.

       KeepBindCapabilities 0|1|auto
           On Linux, when we are started as root and we switch our identity
           using the User option, the KeepBindCapabilities option tells us
           whether to try to retain our ability to bind to low ports. If this
           value is 1, we try to keep the capability; if it is 0 we do not;
           and if it is auto, we keep the capability only if we are configured
           to listen on a low port. Can not be changed while tor is running.
           (Default: auto.)

       HardwareAccel 0|1
           If non-zero, try to use built-in (static) crypto hardware
           acceleration when available. Can not be changed while tor is
           running. (Default: 0)

       AccelName NAME
           When using OpenSSL hardware crypto acceleration attempt to load the
           dynamic engine of this name. This must be used for any dynamic
           hardware engine. Names can be verified with the openssl engine
           command. Can not be changed while tor is running.

       AccelDir DIR
           Specify this option if using dynamic hardware acceleration and the
           engine implementation library resides somewhere other than the
           OpenSSL default. Can not be changed while tor is running.

       AvoidDiskWrites 0|1
           If non-zero, try to write to disk less frequently than we would
           otherwise. This is useful when running on flash memory or other
           media that support only a limited number of writes. (Default: 0)

       CircuitPriorityHalflife NUM
           If this value is set, we override the default algorithm for
           choosing which circuit’s cell to deliver or relay next. It is
           delivered first to the circuit that has the lowest weighted cell
           count, where cells are weighted exponentially according to this
           value (in seconds). If the value is -1, it is taken from the
           consensus if possible else it will fallback to the default value of
           30. Minimum: 1, Maximum: 2147483647. This can be defined as a float
           value. This is an advanced option; you generally shouldn’t have to
           mess with it. (Default: -1)

       CountPrivateBandwidth 0|1
           If this option is set, then Tor’s rate-limiting applies not only to
           remote connections, but also to connections to private addresses
           like 127.0.0.1 or 10.0.0.1. This is mostly useful for debugging
           rate-limiting. (Default: 0)

       ExtendByEd25519ID 0|1|auto
           If this option is set to 1, we always try to include a relay’s
           Ed25519 ID when telling the proceeding relay in a circuit to extend
           to it. If this option is set to 0, we never include Ed25519 IDs
           when extending circuits. If the option is set to "default", we obey
           a parameter in the consensus document. (Default: auto)

       NoExec 0|1
           If this option is set to 1, then Tor will never launch another
           executable, regardless of the settings of ClientTransportPlugin or
           ServerTransportPlugin. Once this option has been set to 1, it
           cannot be set back to 0 without restarting Tor. (Default: 0)

       Schedulers KIST|KISTLite|Vanilla
           Specify the scheduler type that tor should use. The scheduler is
           responsible for moving data around within a Tor process. This is an
           ordered list by priority which means that the first value will be
           tried first and if unavailable, the second one is tried and so on.
           It is possible to change these values at runtime. This option
           mostly effects relays, and most operators should leave it set to
           its default value. (Default: KIST,KISTLite,Vanilla)

           The possible scheduler types are:

           KIST: Kernel-Informed Socket Transport. Tor will use TCP
           information from the kernel to make informed decisions regarding
           how much data to send and when to send it. KIST also handles
           traffic in batches (see KISTSchedRunInterval) in order to improve
           traffic prioritization decisions. As implemented, KIST will only
           work on Linux kernel version 2.6.39 or higher.

           KISTLite: Same as KIST but without kernel support. Tor will use all
           the same mechanics as with KIST, including the batching, but its
           decisions regarding how much data to send will not be as good.
           KISTLite will work on all kernels and operating systems, and the
           majority of the benefits of KIST are still realized with KISTLite.

           Vanilla: The scheduler that Tor used before KIST was implemented.
           It sends as much data as possible, as soon as possible. Vanilla
           will work on all kernels and operating systems.

       KISTSchedRunInterval NUM msec
           If KIST or KISTLite is used in the Schedulers option, this controls
           at which interval the scheduler tick is. If the value is 0 msec,
           the value is taken from the consensus if possible else it will
           fallback to the default 10 msec. Maximum possible value is 100
           msec. (Default: 0 msec)

       KISTSockBufSizeFactor NUM
           If KIST is used in Schedulers, this is a multiplier of the
           per-socket limit calculation of the KIST algorithm. (Default: 1.0)

CLIENT OPTIONS
       The following options are useful only for clients (that is, if
       SocksPort, HTTPTunnelPort, TransPort, DNSPort, or NATDPort is
       non-zero):

       Bridge [transport] IP:ORPort [fingerprint]
           When set along with UseBridges, instructs Tor to use the relay at
           "IP:ORPort" as a "bridge" relaying into the Tor network. If
           "fingerprint" is provided (using the same format as for
           DirAuthority), we will verify that the relay running at that
           location has the right fingerprint. We also use fingerprint to look
           up the bridge descriptor at the bridge authority, if it’s provided
           and if UpdateBridgesFromAuthority is set too.


           If "transport" is provided, it must match a ClientTransportPlugin
           line. We then use that pluggable transport’s proxy to transfer data
           to the bridge, rather than connecting to the bridge directly. Some
           transports use a transport-specific method to work out the remote
           address to connect to. These transports typically ignore the
           "IP:ORPort" specified in the bridge line.


           Tor passes any "key=val" settings to the pluggable transport proxy
           as per-connection arguments when connecting to the bridge. Consult
           the documentation of the pluggable transport for details of what
           arguments it supports.

       LearnCircuitBuildTimeout 0|1
           If 0, CircuitBuildTimeout adaptive learning is disabled. (Default:
           1)

       CircuitBuildTimeout NUM
           Try for at most NUM seconds when building circuits. If the circuit
           isn’t open in that time, give up on it. If LearnCircuitBuildTimeout
           is 1, this value serves as the initial value to use before a
           timeout is learned. If LearnCircuitBuildTimeout is 0, this value is
           the only value used. (Default: 60 seconds)

       CircuitsAvailableTimeout NUM
           Tor will attempt to keep at least one open, unused circuit
           available for this amount of time. This option governs how long
           idle circuits are kept open, as well as the amount of time Tor will
           keep a circuit open to each of the recently used ports. This way
           when the Tor client is entirely idle, it can expire all of its
           circuits, and then expire its TLS connections. Note that the actual
           timeout value is uniformly randomized from the specified value to
           twice that amount. (Default: 30 minutes; Max: 24 hours)

       CircuitStreamTimeout NUM
           If non-zero, this option overrides our internal timeout schedule
           for how many seconds until we detach a stream from a circuit and
           try a new circuit. If your network is particularly slow, you might
           want to set this to a number like 60. (Default: 0)

       ClientOnly 0|1
           If set to 1, Tor will not run as a relay or serve directory
           requests, even if the ORPort, ExtORPort, or DirPort options are
           set. (This config option is mostly unnecessary: we added it back
           when we were considering having Tor clients auto-promote themselves
           to being relays if they were stable and fast enough. The current
           behavior is simply that Tor is a client unless ORPort, ExtORPort,
           or DirPort are configured.) (Default: 0)

       ConnectionPadding 0|1|auto
           This option governs Tor’s use of padding to defend against some
           forms of traffic analysis. If it is set to auto, Tor will send
           padding only if both the client and the relay support it. If it is
           set to 0, Tor will not send any padding cells. If it is set to 1,
           Tor will still send padding for client connections regardless of
           relay support. Only clients may set this option. This option should
           be offered via the UI to mobile users for use where bandwidth may
           be expensive. (Default: auto)

       ReducedConnectionPadding 0|1
           If set to 1, Tor will not not hold OR connections open for very
           long, and will send less padding on these connections. Only clients
           may set this option. This option should be offered via the UI to
           mobile users for use where bandwidth may be expensive. (Default: 0)

       ExcludeNodes node,node,...
           A list of identity fingerprints, country codes, and address
           patterns of nodes to avoid when building a circuit. Country codes
           are 2-letter ISO3166 codes, and must be wrapped in braces;
           fingerprints may be preceded by a dollar sign. (Example:
           ExcludeNodes ABCD1234CDEF5678ABCD1234CDEF5678ABCD1234, {cc},
           255.254.0.0/8)


           By default, this option is treated as a preference that Tor is
           allowed to override in order to keep working. For example, if you
           try to connect to a hidden service, but you have excluded all of
           the hidden service’s introduction points, Tor will connect to one
           of them anyway. If you do not want this behavior, set the
           StrictNodes option (documented below).


           Note also that if you are a relay, this (and the other node
           selection options below) only affects your own circuits that Tor
           builds for you. Clients can still build circuits through you to any
           node. Controllers can tell Tor to build circuits through any node.


           Country codes are case-insensitive. The code "{??}" refers to nodes
           whose country can’t be identified. No country code, including {??},
           works if no GeoIPFile can be loaded. See also the
           GeoIPExcludeUnknown option below.

       ExcludeExitNodes node,node,...
           A list of identity fingerprints, country codes, and address
           patterns of nodes to never use when picking an exit node---that is,
           a node that delivers traffic for you outside the Tor network. Note
           that any node listed in ExcludeNodes is automatically considered to
           be part of this list too. See the ExcludeNodes option for more
           information on how to specify nodes. See also the caveats on the
           "ExitNodes" option below.

       GeoIPExcludeUnknown 0|1|auto
           If this option is set to auto, then whenever any country code is
           set in ExcludeNodes or ExcludeExitNodes, all nodes with unknown
           country ({??} and possibly {A1}) are treated as excluded as well.
           If this option is set to 1, then all unknown countries are treated
           as excluded in ExcludeNodes and ExcludeExitNodes. This option has
           no effect when a GeoIP file isn’t configured or can’t be found.
           (Default: auto)

       ExitNodes node,node,...
           A list of identity fingerprints, country codes, and address
           patterns of nodes to use as exit node---that is, a node that
           delivers traffic for you outside the Tor network. See the
           ExcludeNodes option for more information on how to specify nodes.


           Note that if you list too few nodes here, or if you exclude too
           many exit nodes with ExcludeExitNodes, you can degrade
           functionality. For example, if none of the exits you list allows
           traffic on port 80 or 443, you won’t be able to browse the web.


           Note also that not every circuit is used to deliver traffic outside
           of the Tor network. It is normal to see non-exit circuits (such as
           those used to connect to hidden services, those that do directory
           fetches, those used for relay reachability self-tests, and so on)
           that end at a non-exit node. To keep a node from being used
           entirely, see ExcludeNodes and StrictNodes.


           The ExcludeNodes option overrides this option: any node listed in
           both ExitNodes and ExcludeNodes is treated as excluded.


           The .exit address notation, if enabled via MapAddress, overrides
           this option.

       EntryNodes node,node,...
           A list of identity fingerprints and country codes of nodes to use
           for the first hop in your normal circuits. Normal circuits include
           all circuits except for direct connections to directory servers.
           The Bridge option overrides this option; if you have configured
           bridges and UseBridges is 1, the Bridges are used as your entry
           nodes.


           The ExcludeNodes option overrides this option: any node listed in
           both EntryNodes and ExcludeNodes is treated as excluded. See the
           ExcludeNodes option for more information on how to specify nodes.

       StrictNodes 0|1
           If StrictNodes is set to 1, Tor will treat solely the ExcludeNodes
           option as a requirement to follow for all the circuits you
           generate, even if doing so will break functionality for you
           (StrictNodes applies to neither ExcludeExitNodes nor to ExitNodes).
           If StrictNodes is set to 0, Tor will still try to avoid nodes in
           the ExcludeNodes list, but it will err on the side of avoiding
           unexpected errors. Specifically, StrictNodes 0 tells Tor that it is
           okay to use an excluded node when it is necessary to perform relay
           reachability self-tests, connect to a hidden service, provide a
           hidden service to a client, fulfill a .exit request, upload
           directory information, or download directory information. (Default:
           0)

       FascistFirewall 0|1
           If 1, Tor will only create outgoing connections to ORs running on
           ports that your firewall allows (defaults to 80 and 443; see
           FirewallPorts). This will allow you to run Tor as a client behind a
           firewall with restrictive policies, but will not allow you to run
           as a server behind such a firewall. If you prefer more fine-grained
           control, use ReachableAddresses instead.

       FirewallPorts PORTS
           A list of ports that your firewall allows you to connect to. Only
           used when FascistFirewall is set. This option is deprecated; use
           ReachableAddresses instead. (Default: 80, 443)

       ReachableAddresses IP[/MASK][:PORT]...
           A comma-separated list of IP addresses and ports that your firewall
           allows you to connect to. The format is as for the addresses in
           ExitPolicy, except that "accept" is understood unless "reject" is
           explicitly provided. For example, 'ReachableAddresses 99.0.0.0/8,
           reject 18.0.0.0/8:80, accept *:80' means that your firewall allows
           connections to everything inside net 99, rejects port 80
           connections to net 18, and accepts connections to port 80
           otherwise. (Default: 'accept *:*'.)

       ReachableDirAddresses IP[/MASK][:PORT]...
           Like ReachableAddresses, a list of addresses and ports. Tor will
           obey these restrictions when fetching directory information, using
           standard HTTP GET requests. If not set explicitly then the value of
           ReachableAddresses is used. If HTTPProxy is set then these
           connections will go through that proxy. (DEPRECATED: This option
           has had no effect for some time.)

       ReachableORAddresses IP[/MASK][:PORT]...
           Like ReachableAddresses, a list of addresses and ports. Tor will
           obey these restrictions when connecting to Onion Routers, using
           TLS/SSL. If not set explicitly then the value of ReachableAddresses
           is used. If HTTPSProxy is set then these connections will go
           through that proxy.


           The separation between ReachableORAddresses and
           ReachableDirAddresses is only interesting when you are connecting
           through proxies (see HTTPProxy and HTTPSProxy). Most proxies limit
           TLS connections (which Tor uses to connect to Onion Routers) to
           port 443, and some limit HTTP GET requests (which Tor uses for
           fetching directory information) to port 80.

       HidServAuth onion-address auth-cookie [service-name]
           Client authorization for a hidden service. Valid onion addresses
           contain 16 characters in a-z2-7 plus ".onion", and valid auth
           cookies contain 22 characters in A-Za-z0-9+/. The service name is
           only used for internal purposes, e.g., for Tor controllers. This
           option may be used multiple times for different hidden services. If
           a hidden service uses authorization and this option is not set, the
           hidden service is not accessible. Hidden services can be configured
           to require authorization using the HiddenServiceAuthorizeClient
           option.

       ClientOnionAuthDir path
           Path to the directory containing v3 hidden service authorization
           files. Each file is for a single onion address, and the files MUST
           have the suffix ".auth_private" (i.e. "bob_onion.auth_private").
           The content format MUST be:

           <onion-address>:descriptor:x25519:<base32-encoded-privkey>

           The <onion-address> MUST NOT have the ".onion" suffix. The
           <base32-encoded-privkey> is the base32 representation of the raw
           key bytes only (32 bytes for x25519). See Appendix G in the
           rend-spec-v3.txt file of torspec for more information.

       LongLivedPorts PORTS
           A list of ports for services that tend to have long-running
           connections (e.g. chat and interactive shells). Circuits for
           streams that use these ports will contain only high-uptime nodes,
           to reduce the chance that a node will go down before the stream is
           finished. Note that the list is also honored for circuits (both
           client and service side) involving hidden services whose virtual
           port is in this list. (Default: 21, 22, 706, 1863, 5050, 5190,
           5222, 5223, 6523, 6667, 6697, 8300)

       MapAddress address newaddress
           When a request for address arrives to Tor, it will transform to
           newaddress before processing it. For example, if you always want
           connections to www.example.com to exit via torserver (where
           torserver is the fingerprint of the server), use "MapAddress
           www.example.com www.example.com.torserver.exit". If the value is
           prefixed with a "*.", matches an entire domain. For example, if you
           always want connections to example.com and any if its subdomains to
           exit via torserver (where torserver is the fingerprint of the
           server), use "MapAddress *.example.com
           *.example.com.torserver.exit". (Note the leading "*." in each part
           of the directive.) You can also redirect all subdomains of a domain
           to a single address. For example, "MapAddress *.example.com
           www.example.com".


           NOTES:

            1. When evaluating MapAddress expressions Tor stops when it hits
               the most recently added expression that matches the requested
               address. So if you have the following in your torrc,
               www.torproject.org will map to 1.1.1.1:

                   MapAddress www.torproject.org 2.2.2.2
                   MapAddress www.torproject.org 1.1.1.1

            2. Tor evaluates the MapAddress configuration until it finds no
               matches. So if you have the following in your torrc,
               www.torproject.org will map to 2.2.2.2:

                   MapAddress 1.1.1.1 2.2.2.2
                   MapAddress www.torproject.org 1.1.1.1

            3. The following MapAddress expression is invalid (and will be
               ignored) because you cannot map from a specific address to a
               wildcard address:

                   MapAddress www.torproject.org *.torproject.org.torserver.exit

            4. Using a wildcard to match only part of a string (as in
               *ample.com) is also invalid.

       NewCircuitPeriod NUM
           Every NUM seconds consider whether to build a new circuit.
           (Default: 30 seconds)

       MaxCircuitDirtiness NUM
           Feel free to reuse a circuit that was first used at most NUM
           seconds ago, but never attach a new stream to a circuit that is too
           old. For hidden services, this applies to the last time a circuit
           was used, not the first. Circuits with streams constructed with
           SOCKS authentication via SocksPorts that have
           KeepAliveIsolateSOCKSAuth also remain alive for MaxCircuitDirtiness
           seconds after carrying the last such stream. (Default: 10 minutes)

       MaxClientCircuitsPending NUM
           Do not allow more than NUM circuits to be pending at a time for
           handling client streams. A circuit is pending if we have begun
           constructing it, but it has not yet been completely constructed.
           (Default: 32)

       NodeFamily node,node,...
           The Tor servers, defined by their identity fingerprints, constitute
           a "family" of similar or co-administered servers, so never use any
           two of them in the same circuit. Defining a NodeFamily is only
           needed when a server doesn’t list the family itself (with
           MyFamily). This option can be used multiple times; each instance
           defines a separate family. In addition to nodes, you can also list
           IP address and ranges and country codes in {curly braces}. See the
           ExcludeNodes option for more information on how to specify nodes.

       EnforceDistinctSubnets 0|1
           If 1, Tor will not put two servers whose IP addresses are "too
           close" on the same circuit. Currently, two addresses are "too
           close" if they lie in the same /16 range. (Default: 1)

       SocksPort [address:]port|unix:path|auto [flags] [isolation flags]
           Open this port to listen for connections from SOCKS-speaking
           applications. Set this to 0 if you don’t want to allow application
           connections via SOCKS. Set it to "auto" to have Tor pick a port for
           you. This directive can be specified multiple times to bind to
           multiple addresses/ports. If a unix domain socket is used, you may
           quote the path using standard C escape sequences. (Default: 9050)


           NOTE: Although this option allows you to specify an IP address
           other than localhost, you should do so only with extreme caution.
           The SOCKS protocol is unencrypted and (as we use it)
           unauthenticated, so exposing it in this way could leak your
           information to anybody watching your network, and allow anybody to
           use your computer as an open proxy.


           The isolation flags arguments give Tor rules for which streams
           received on this SocksPort are allowed to share circuits with one
           another. Recognized isolation flags are:

           IsolateClientAddr
               Don’t share circuits with streams from a different client
               address. (On by default and strongly recommended when
               supported; you can disable it with NoIsolateClientAddr.
               Unsupported and force-disabled when using Unix domain sockets.)

           IsolateSOCKSAuth
               Don’t share circuits with streams for which different SOCKS
               authentication was provided. (For HTTPTunnelPort connections,
               this option looks at the Proxy-Authorization and
               X-Tor-Stream-Isolation headers. On by default; you can disable
               it with NoIsolateSOCKSAuth.)

           IsolateClientProtocol
               Don’t share circuits with streams using a different protocol.
               (SOCKS 4, SOCKS 5, TransPort connections, NATDPort connections,
               and DNSPort requests are all considered to be different
               protocols.)

           IsolateDestPort
               Don’t share circuits with streams targeting a different
               destination port.

           IsolateDestAddr
               Don’t share circuits with streams targeting a different
               destination address.

           KeepAliveIsolateSOCKSAuth
               If IsolateSOCKSAuth is enabled, keep alive circuits while they
               have at least one stream with SOCKS authentication active.
               After such a circuit is idle for more than MaxCircuitDirtiness
               seconds, it can be closed.

           SessionGroup=INT
               If no other isolation rules would prevent it, allow streams on
               this port to share circuits with streams from every other port
               with the same session group. (By default, streams received on
               different SocksPorts, TransPorts, etc are always isolated from
               one another. This option overrides that behavior.)

           Other recognized flags for a SocksPort are:

           NoIPv4Traffic
               Tell exits to not connect to IPv4 addresses in response to
               SOCKS requests on this connection.

           IPv6Traffic
               Tell exits to allow IPv6 addresses in response to SOCKS
               requests on this connection, so long as SOCKS5 is in use.
               (SOCKS4 can’t handle IPv6.)

           PreferIPv6
               Tells exits that, if a host has both an IPv4 and an IPv6
               address, we would prefer to connect to it via IPv6. (IPv4 is
               the default.)

           NoDNSRequest
               Do not ask exits to resolve DNS addresses in SOCKS5 requests.
               Tor will connect to IPv4 addresses, IPv6 addresses (if
               IPv6Traffic is set) and .onion addresses.

           NoOnionTraffic
               Do not connect to .onion addresses in SOCKS5 requests.

           OnionTrafficOnly
               Tell the tor client to only connect to .onion addresses in
               response to SOCKS5 requests on this connection. This is
               equivalent to NoDNSRequest, NoIPv4Traffic, NoIPv6Traffic. The
               corresponding NoOnionTrafficOnly flag is not supported.

           CacheIPv4DNS
               Tells the client to remember IPv4 DNS answers we receive from
               exit nodes via this connection.

           CacheIPv6DNS
               Tells the client to remember IPv6 DNS answers we receive from
               exit nodes via this connection.

           GroupWritable
               Unix domain sockets only: makes the socket get created as
               group-writable.

           WorldWritable
               Unix domain sockets only: makes the socket get created as
               world-writable.

           CacheDNS
               Tells the client to remember all DNS answers we receive from
               exit nodes via this connection.

           UseIPv4Cache
               Tells the client to use any cached IPv4 DNS answers we have
               when making requests via this connection. (NOTE: This option,
               or UseIPv6Cache or UseDNSCache, can harm your anonymity, and
               probably won’t help performance as much as you might expect.
               Use with care!)

           UseIPv6Cache
               Tells the client to use any cached IPv6 DNS answers we have
               when making requests via this connection.

           UseDNSCache
               Tells the client to use any cached DNS answers we have when
               making requests via this connection.

           PreferIPv6Automap
               When serving a hostname lookup request on this port that should
               get automapped (according to AutomapHostsOnResolve), if we
               could return either an IPv4 or an IPv6 answer, prefer an IPv6
               answer. (On by default.)

           PreferSOCKSNoAuth
               Ordinarily, when an application offers both "username/password
               authentication" and "no authentication" to Tor via SOCKS5, Tor
               selects username/password authentication so that
               IsolateSOCKSAuth can work. This can confuse some applications,
               if they offer a username/password combination then get confused
               when asked for one. You can disable this behavior, so that Tor
               will select "No authentication" when IsolateSOCKSAuth is
               disabled, or when this option is set.

           Flags are processed left to right. If flags conflict, the last flag
           on the line is used, and all earlier flags are ignored. No error is
           issued for conflicting flags.

       SocksPolicy policy,policy,...
           Set an entrance policy for this server, to limit who can connect to
           the SocksPort and DNSPort ports. The policies have the same form as
           exit policies below, except that port specifiers are ignored. Any
           address not matched by some entry in the policy is accepted.

       SocksTimeout NUM
           Let a socks connection wait NUM seconds handshaking, and NUM
           seconds unattached waiting for an appropriate circuit, before we
           fail it. (Default: 2 minutes)

       TokenBucketRefillInterval NUM [msec|second]
           Set the refill delay interval of Tor’s token bucket to NUM
           milliseconds. NUM must be between 1 and 1000, inclusive. When Tor
           is out of bandwidth, on a connection or globally, it will wait up
           to this long before it tries to use that connection again. Note
           that bandwidth limits are still expressed in bytes per second: this
           option only affects the frequency with which Tor checks to see
           whether previously exhausted connections may read again. Can not be
           changed while tor is running. (Default: 100 msec)

       TrackHostExits host,.domain,...
           For each value in the comma separated list, Tor will track recent
           connections to hosts that match this value and attempt to reuse the
           same exit node for each. If the value is prepended with a '.', it
           is treated as matching an entire domain. If one of the values is
           just a '.', it means match everything. This option is useful if you
           frequently connect to sites that will expire all your
           authentication cookies (i.e. log you out) if your IP address
           changes. Note that this option does have the disadvantage of making
           it more clear that a given history is associated with a single
           user. However, most people who would wish to observe this will
           observe it through cookies or other protocol-specific means anyhow.

       TrackHostExitsExpire NUM
           Since exit servers go up and down, it is desirable to expire the
           association between host and exit server after NUM seconds. The
           default is 1800 seconds (30 minutes).

       UpdateBridgesFromAuthority 0|1
           When set (along with UseBridges), Tor will try to fetch bridge
           descriptors from the configured bridge authorities when feasible.
           It will fall back to a direct request if the authority responds
           with a 404. (Default: 0)

       UseBridges 0|1
           When set, Tor will fetch descriptors for each bridge listed in the
           "Bridge" config lines, and use these relays as both entry guards
           and directory guards. (Default: 0)

       UseEntryGuards 0|1
           If this option is set to 1, we pick a few long-term entry servers,
           and try to stick with them. This is desirable because constantly
           changing servers increases the odds that an adversary who owns some
           servers will observe a fraction of your paths. Entry Guards can not
           be used by Directory Authorities or Single Onion Services. In these
           cases, this option is ignored. (Default: 1)

       GuardfractionFile FILENAME
           V3 authoritative directories only. Configures the location of the
           guardfraction file which contains information about how long relays
           have been guards. (Default: unset)

       UseGuardFraction 0|1|auto
           This option specifies whether clients should use the guardfraction
           information found in the consensus during path selection. If it’s
           set to auto, clients will do what the UseGuardFraction consensus
           parameter tells them to do. (Default: auto)

       NumEntryGuards NUM
           If UseEntryGuards is set to 1, we will try to pick a total of NUM
           routers as long-term entries for our circuits. If NUM is 0, we try
           to learn the number from the guard-n-primary-guards-to-use
           consensus parameter, and default to 1 if the consensus parameter
           isn’t set. (Default: 0)

       NumPrimaryGuards NUM
           If UseEntryGuards is set to 1, we will try to pick NUM routers for
           our primary guard list, which is the set of routers we strongly
           prefer when connecting to the Tor network. If NUM is 0, we try to
           learn the number from the guard-n-primary-guards consensus
           parameter, and default to 3 if the consensus parameter isn’t set.
           (Default: 0)

       NumDirectoryGuards NUM
           If UseEntryGuards is set to 1, we try to make sure we have at least
           NUM routers to use as directory guards. If this option is set to 0,
           use the value from the guard-n-primary-dir-guards-to-use consensus
           parameter, and default to 3 if the consensus parameter isn’t set.
           (Default: 0)

       GuardLifetime N days|weeks|months
           If nonzero, and UseEntryGuards is set, minimum time to keep a guard
           before picking a new one. If zero, we use the GuardLifetime
           parameter from the consensus directory. No value here may be less
           than 1 month or greater than 5 years; out-of-range values are
           clamped. (Default: 0)

       SafeSocks 0|1
           When this option is enabled, Tor will reject application
           connections that use unsafe variants of the socks protocol — ones
           that only provide an IP address, meaning the application is doing a
           DNS resolve first. Specifically, these are socks4 and socks5 when
           not doing remote DNS. (Default: 0)

       TestSocks 0|1
           When this option is enabled, Tor will make a notice-level log entry
           for each connection to the Socks port indicating whether the
           request used a safe socks protocol or an unsafe one (see above
           entry on SafeSocks). This helps to determine whether an application
           using Tor is possibly leaking DNS requests. (Default: 0)

       VirtualAddrNetworkIPv4 IPv4Address/bits

       VirtualAddrNetworkIPv6 [IPv6Address]/bits
           When Tor needs to assign a virtual (unused) address because of a
           MAPADDRESS command from the controller or the AutomapHostsOnResolve
           feature, Tor picks an unassigned address from this range.
           (Defaults: 127.192.0.0/10 and [FE80::]/10 respectively.)


           When providing proxy server service to a network of computers using
           a tool like dns-proxy-tor, change the IPv4 network to
           "10.192.0.0/10" or "172.16.0.0/12" and change the IPv6 network to
           "[FC00::]/7". The default VirtualAddrNetwork address ranges on a
           properly configured machine will route to the loopback or
           link-local interface. The maximum number of bits for the network
           prefix is set to 104 for IPv6 and 16 for IPv4. However, a wider
           network - smaller prefix length

           ·   is preferable since it reduces the chances for an attacker to
               guess the used IP. For local use, no change to the default
               VirtualAddrNetwork setting is needed.

       AllowNonRFC953Hostnames 0|1
           When this option is disabled, Tor blocks hostnames containing
           illegal characters (like @ and :) rather than sending them to an
           exit node to be resolved. This helps trap accidental attempts to
           resolve URLs and so on. (Default: 0)

       HTTPTunnelPort [address:]port|auto [isolation flags]
           Open this port to listen for proxy connections using the "HTTP
           CONNECT" protocol instead of SOCKS. Set this to 0 if you don’t want
           to allow "HTTP CONNECT" connections. Set the port to "auto" to have
           Tor pick a port for you. This directive can be specified multiple
           times to bind to multiple addresses/ports. See SOCKSPort for an
           explanation of isolation flags. (Default: 0)

       TransPort [address:]port|auto [isolation flags]
           Open this port to listen for transparent proxy connections. Set
           this to 0 if you don’t want to allow transparent proxy connections.
           Set the port to "auto" to have Tor pick a port for you. This
           directive can be specified multiple times to bind to multiple
           addresses/ports. See SOCKSPort for an explanation of isolation
           flags.


           TransPort requires OS support for transparent proxies, such as
           BSDs' pf or Linux’s IPTables. If you’re planning to use Tor as a
           transparent proxy for a network, you’ll want to examine and change
           VirtualAddrNetwork from the default setting. (Default: 0)

       TransProxyType default|TPROXY|ipfw|pf-divert
           TransProxyType may only be enabled when there is transparent proxy
           listener enabled.


           Set this to "TPROXY" if you wish to be able to use the TPROXY Linux
           module to transparently proxy connections that are configured using
           the TransPort option. Detailed information on how to configure the
           TPROXY feature can be found in the Linux kernel source tree in the
           file Documentation/networking/tproxy.txt.


           Set this option to "ipfw" to use the FreeBSD ipfw interface.


           On *BSD operating systems when using pf, set this to "pf-divert" to
           take advantage of divert-to rules, which do not modify the packets
           like rdr-to rules do. Detailed information on how to configure pf
           to use divert-to rules can be found in the pf.conf(5) manual page.
           On OpenBSD, divert-to is available to use on versions greater than
           or equal to OpenBSD 4.4.


           Set this to "default", or leave it unconfigured, to use regular
           IPTables on Linux, or to use pf rdr-to rules on *BSD systems.


           (Default: "default")

       NATDPort [address:]port|auto [isolation flags]
           Open this port to listen for connections from old versions of ipfw
           (as included in old versions of FreeBSD, etc) using the NATD
           protocol. Use 0 if you don’t want to allow NATD connections. Set
           the port to "auto" to have Tor pick a port for you. This directive
           can be specified multiple times to bind to multiple
           addresses/ports. See SocksPort for an explanation of isolation
           flags.


           This option is only for people who cannot use TransPort. (Default:
           0)

       AutomapHostsOnResolve 0|1
           When this option is enabled, and we get a request to resolve an
           address that ends with one of the suffixes in AutomapHostsSuffixes,
           we map an unused virtual address to that address, and return the
           new virtual address. This is handy for making ".onion" addresses
           work with applications that resolve an address and then connect to
           it. (Default: 0)

       AutomapHostsSuffixes SUFFIX,SUFFIX,...
           A comma-separated list of suffixes to use with
           AutomapHostsOnResolve. The "." suffix is equivalent to "all
           addresses." (Default: .exit,.onion).

       DNSPort [address:]port|auto [isolation flags]
           If non-zero, open this port to listen for UDP DNS requests, and
           resolve them anonymously. This port only handles A, AAAA, and PTR
           requests---it doesn’t handle arbitrary DNS request types. Set the
           port to "auto" to have Tor pick a port for you. This directive can
           be specified multiple times to bind to multiple addresses/ports.
           See SocksPort for an explanation of isolation flags. (Default: 0)

       ClientDNSRejectInternalAddresses 0|1
           If true, Tor does not believe any anonymously retrieved DNS answer
           that tells it that an address resolves to an internal address (like
           127.0.0.1 or 192.168.0.1). This option prevents certain
           browser-based attacks; it is not allowed to be set on the default
           network. (Default: 1)

       ClientRejectInternalAddresses 0|1
           If true, Tor does not try to fulfill requests to connect to an
           internal address (like 127.0.0.1 or 192.168.0.1) unless an exit
           node is specifically requested (for example, via a .exit hostname,
           or a controller request). If true, multicast DNS hostnames for
           machines on the local network (of the form *.local) are also
           rejected. (Default: 1)

       DownloadExtraInfo 0|1
           If true, Tor downloads and caches "extra-info" documents. These
           documents contain information about servers other than the
           information in their regular server descriptors. Tor does not use
           this information for anything itself; to save bandwidth, leave this
           option turned off. (Default: 0)

       WarnPlaintextPorts port,port,...
           Tells Tor to issue a warnings whenever the user tries to make an
           anonymous connection to one of these ports. This option is designed
           to alert users to services that risk sending passwords in the
           clear. (Default: 23,109,110,143)

       RejectPlaintextPorts port,port,...
           Like WarnPlaintextPorts, but instead of warning about risky port
           uses, Tor will instead refuse to make the connection. (Default:
           None)

       OptimisticData 0|1|auto
           When this option is set, and Tor is using an exit node that
           supports the feature, it will try optimistically to send data to
           the exit node without waiting for the exit node to report whether
           the connection succeeded. This can save a round-trip time for
           protocols like HTTP where the client talks first. If OptimisticData
           is set to auto, Tor will look at the UseOptimisticData parameter in
           the networkstatus. (Default: auto)

       HSLayer2Nodes node,node,...
           A list of identity fingerprints, nicknames, country codes, and
           address patterns of nodes that are allowed to be used as the second
           hop in all client or service-side Onion Service circuits. This
           option mitigates attacks where the adversary runs middle nodes and
           induces your client or service to create many circuits, in order to
           discover your primary guard node. (Default: Any node in the network
           may be used in the second hop.)

           (Example: HSLayer2Nodes ABCD1234CDEF5678ABCD1234CDEF5678ABCD1234,
           {cc}, 255.254.0.0/8)


           When this is set, the resulting hidden service paths will look
           like:

           C - G - L2 - M - Rend

           C - G - L2 - M - HSDir

           C - G - L2 - M - Intro

           S - G - L2 - M - Rend

           S - G - L2 - M - HSDir

           S - G - L2 - M - Intro


           where C is this client, S is the service, G is the Guard node, L2
           is a node from this option, and M is a random middle node. Rend,
           HSDir, and Intro point selection is not affected by this option.

           This option may be combined with HSLayer3Nodes to create paths of
           the form:

           C - G - L2 - L3 - Rend

           C - G - L2 - L3 - M - HSDir

           C - G - L2 - L3 - M - Intro

           S - G - L2 - L3 - M - Rend

           S - G - L2 - L3 - HSDir

           S - G - L2 - L3 - Intro


           ExcludeNodes have higher priority than HSLayer2Nodes, which means
           that nodes specified in ExcludeNodes will not be picked.

           When either this option or HSLayer3Nodes are set, the /16 subnet
           and node family restrictions are removed for hidden service
           circuits. Additionally, we allow the guard node to be present as
           the Rend, HSDir, and IP node, and as the hop before it. This is
           done to prevent the adversary from inferring information about our
           guard, layer2, and layer3 node choices at later points in the path.

           This option is meant to be managed by a Tor controller such as
           https://github.com/mikeperry-tor/vanguards that selects and updates
           this set of nodes for you. Hence it does not do load balancing if
           fewer than 20 nodes are selected, and if no nodes in HSLayer2Nodes
           are currently available for use, Tor will not work. Please use
           extreme care if you are setting this option manually.

       HSLayer3Nodes node,node,...
           A list of identity fingerprints, nicknames, country codes, and
           address patterns of nodes that are allowed to be used as the third
           hop in all client and service-side Onion Service circuits. This
           option mitigates attacks where the adversary runs middle nodes and
           induces your client or service to create many circuits, in order to
           discover your primary or Layer2 guard nodes. (Default: Any node in
           the network may be used in the third hop.)

           (Example: HSLayer3Nodes ABCD1234CDEF5678ABCD1234CDEF5678ABCD1234,
           {cc}, 255.254.0.0/8)


           When this is set by itself, the resulting hidden service paths will
           look like:

           C - G - M - L3 - Rend

           C - G - M - L3 - M - HSDir

           C - G - M - L3 - M - Intro

           S - G - M - L3 - M - Rend

           S - G - M - L3 - HSDir

           S - G - M - L3 - Intro

           where C is this client, S is the service, G is the Guard node, L2
           is a node from this option, and M is a random middle node. Rend,
           HSDir, and Intro point selection is not affected by this option.

           While it is possible to use this option by itself, it should be
           combined with HSLayer2Nodes to create paths of the form:

           C - G - L2 - L3 - Rend

           C - G - L2 - L3 - M - HSDir

           C - G - L2 - L3 - M - Intro

           S - G - L2 - L3 - M - Rend

           S - G - L2 - L3 - HSDir

           S - G - L2 - L3 - Intro


           ExcludeNodes have higher priority than HSLayer3Nodes, which means
           that nodes specified in ExcludeNodes will not be picked.

           When either this option or HSLayer2Nodes are set, the /16 subnet
           and node family restrictions are removed for hidden service
           circuits. Additionally, we allow the guard node to be present as
           the Rend, HSDir, and IP node, and as the hop before it. This is
           done to prevent the adversary from inferring information about our
           guard, layer2, and layer3 node choices at later points in the path.

           This option is meant to be managed by a Tor controller such as
           https://github.com/mikeperry-tor/vanguards that selects and updates
           this set of nodes for you. Hence it does not do load balancing if
           fewer than 20 nodes are selected, and if no nodes in HSLayer3Nodes
           are currently available for use, Tor will not work. Please use
           extreme care if you are setting this option manually.

       UseMicrodescriptors 0|1|auto
           Microdescriptors are a smaller version of the information that Tor
           needs in order to build its circuits. Using microdescriptors makes
           Tor clients download less directory information, thus saving
           bandwidth. Directory caches need to fetch regular descriptors and
           microdescriptors, so this option doesn’t save any bandwidth for
           them. For legacy reasons, auto is accepted, but it has the same
           effect as 1. (Default: auto)

       PathBiasCircThreshold NUM

       PathBiasNoticeRate NUM

       PathBiasWarnRate NUM

       PathBiasExtremeRate NUM

       PathBiasDropGuards NUM

       PathBiasScaleThreshold NUM
           These options override the default behavior of Tor’s (currently
           experimental) path bias detection algorithm. To try to find broken
           or misbehaving guard nodes, Tor looks for nodes where more than a
           certain fraction of circuits through that guard fail to get built.


           The PathBiasCircThreshold option controls how many circuits we need
           to build through a guard before we make these checks. The
           PathBiasNoticeRate, PathBiasWarnRate and PathBiasExtremeRate
           options control what fraction of circuits must succeed through a
           guard so we won’t write log messages. If less than
           PathBiasExtremeRate circuits succeed and PathBiasDropGuards is set
           to 1, we disable use of that guard.


           When we have seen more than PathBiasScaleThreshold circuits through
           a guard, we scale our observations by 0.5 (governed by the
           consensus) so that new observations don’t get swamped by old ones.


           By default, or if a negative value is provided for one of these
           options, Tor uses reasonable defaults from the networkstatus
           consensus document. If no defaults are available there, these
           options default to 150, .70, .50, .30, 0, and 300 respectively.

       PathBiasUseThreshold NUM

       PathBiasNoticeUseRate NUM

       PathBiasExtremeUseRate NUM

       PathBiasScaleUseThreshold NUM
           Similar to the above options, these options override the default
           behavior of Tor’s (currently experimental) path use bias detection
           algorithm.


           Where as the path bias parameters govern thresholds for
           successfully building circuits, these four path use bias parameters
           govern thresholds only for circuit usage. Circuits which receive no
           stream usage are not counted by this detection algorithm. A used
           circuit is considered successful if it is capable of carrying
           streams or otherwise receiving well-formed responses to RELAY
           cells.


           By default, or if a negative value is provided for one of these
           options, Tor uses reasonable defaults from the networkstatus
           consensus document. If no defaults are available there, these
           options default to 20, .80, .60, and 100, respectively.

       ClientUseIPv4 0|1
           If this option is set to 0, Tor will avoid connecting to directory
           servers and entry nodes over IPv4. Note that clients with an IPv4
           address in a Bridge, proxy, or pluggable transport line will try
           connecting over IPv4 even if ClientUseIPv4 is set to 0. (Default:
           1)

       ClientUseIPv6 0|1
           If this option is set to 1, Tor might connect to directory servers
           or entry nodes over IPv6. For IPv6 only hosts, you need to also set
           ClientUseIPv4 to 0 to disable IPv4. Note that clients configured
           with an IPv6 address in a Bridge, proxy, or pluggable transportline
           will try connecting over IPv6 even if ClientUseIPv6 is set to 0.
           (Default: 0)

       ClientPreferIPv6DirPort 0|1|auto
           If this option is set to 1, Tor prefers a directory port with an
           IPv6 address over one with IPv4, for direct connections, if a given
           directory server has both. (Tor also prefers an IPv6 DirPort if
           IPv4Client is set to 0.) If this option is set to auto, clients
           prefer IPv4. Other things may influence the choice. This option
           breaks a tie to the favor of IPv6. (Default: auto) (DEPRECATED:
           This option has had no effect for some time.)

       ClientPreferIPv6ORPort 0|1|auto
           If this option is set to 1, Tor prefers an OR port with an IPv6
           address over one with IPv4 if a given entry node has both. (Tor
           also prefers an IPv6 ORPort if IPv4Client is set to 0.) If this
           option is set to auto, Tor bridge clients prefer the configured
           bridge address, and other clients prefer IPv4. Other things may
           influence the choice. This option breaks a tie to the favor of
           IPv6. (Default: auto)

       PathsNeededToBuildCircuits NUM
           Tor clients don’t build circuits for user traffic until they know
           about enough of the network so that they could potentially
           construct enough of the possible paths through the network. If this
           option is set to a fraction between 0.25 and 0.95, Tor won’t build
           circuits until it has enough descriptors or microdescriptors to
           construct that fraction of possible paths. Note that setting this
           option too low can make your Tor client less anonymous, and setting
           it too high can prevent your Tor client from bootstrapping. If this
           option is negative, Tor will use a default value chosen by the
           directory authorities. If the directory authorities do not choose a
           value, Tor will default to 0.6. (Default: -1)

       ClientBootstrapConsensusAuthorityDownloadInitialDelay N
           Initial delay in seconds for when clients should download
           consensuses from authorities if they are bootstrapping (that is,
           they don’t have a usable, reasonably live consensus). Only used by
           clients fetching from a list of fallback directory mirrors. This
           schedule is advanced by (potentially concurrent) connection
           attempts, unlike other schedules, which are advanced by connection
           failures. (Default: 6)

       ClientBootstrapConsensusFallbackDownloadInitialDelay N
           Initial delay in seconds for when clients should download
           consensuses from fallback directory mirrors if they are
           bootstrapping (that is, they don’t have a usable, reasonably live
           consensus). Only used by clients fetching from a list of fallback
           directory mirrors. This schedule is advanced by (potentially
           concurrent) connection attempts, unlike other schedules, which are
           advanced by connection failures. (Default: 0)

       ClientBootstrapConsensusAuthorityOnlyDownloadInitialDelay N
           Initial delay in seconds for when clients should download
           consensuses from authorities if they are bootstrapping (that is,
           they don’t have a usable, reasonably live consensus). Only used by
           clients which don’t have or won’t fetch from a list of fallback
           directory mirrors. This schedule is advanced by (potentially
           concurrent) connection attempts, unlike other schedules, which are
           advanced by connection failures. (Default: 0)

       ClientBootstrapConsensusMaxInProgressTries NUM
           Try this many simultaneous connections to download a consensus
           before waiting for one to complete, timeout, or error out.
           (Default: 3)

SERVER OPTIONS
       The following options are useful only for servers (that is, if ORPort
       is non-zero):

       Address address
           The IPv4 address of this server, or a fully qualified domain name
           of this server that resolves to an IPv4 address. You can leave this
           unset, and Tor will try to guess your IPv4 address. This IPv4
           address is the one used to tell clients and other servers where to
           find your Tor server; it doesn’t affect the address that your
           server binds to. To bind to a different address, use the ORPort and
           OutboundBindAddress options.

       AssumeReachable 0|1
           This option is used when bootstrapping a new Tor network. If set to
           1, don’t do self-reachability testing; just upload your server
           descriptor immediately. If AuthoritativeDirectory is also set, this
           option instructs the dirserver to bypass remote reachability
           testing too and list all connected servers as running.

       BridgeRelay 0|1
           Sets the relay to act as a "bridge" with respect to relaying
           connections from bridge users to the Tor network. It mainly causes
           Tor to publish a server descriptor to the bridge database, rather
           than to the public directory authorities.


           Note: make sure that no MyFamily lines are present in your torrc
           when relay is configured in bridge mode.

       BridgeDistribution string
           If set along with BridgeRelay, Tor will include a new line in its
           bridge descriptor which indicates to the BridgeDB service how it
           would like its bridge address to be given out. Set it to "none" if
           you want BridgeDB to avoid distributing your bridge address, or
           "any" to let BridgeDB decide. (Default: any)

           Note: as of Oct 2017, the BridgeDB part of this option is not yet
           implemented. Until BridgeDB is updated to obey this option, your
           bridge will make this request, but it will not (yet) be obeyed.

       ContactInfo email_address
           Administrative contact information for this relay or bridge. This
           line can be used to contact you if your relay or bridge is
           misconfigured or something else goes wrong. Note that we archive
           and publish all descriptors containing these lines and that Google
           indexes them, so spammers might also collect them. You may want to
           obscure the fact that it’s an email address and/or generate a new
           address for this purpose.


           ContactInfo must be set to a working address if you run more than
           one relay or bridge. (Really, everybody running a relay or bridge
           should set it.)

       ExitRelay 0|1|auto
           Tells Tor whether to run as an exit relay. If Tor is running as a
           non-bridge server, and ExitRelay is set to 1, then Tor allows
           traffic to exit according to the ExitPolicy option (or the default
           ExitPolicy if none is specified).


           If ExitRelay is set to 0, no traffic is allowed to exit, and the
           ExitPolicy option is ignored.


           If ExitRelay is set to "auto", then Tor behaves as if it were set
           to 1, but warns the user if this would cause traffic to exit. In a
           future version, the default value will be 0. (Default: auto)

       ExitPolicy policy,policy,...
           Set an exit policy for this server. Each policy is of the form
           "accept[6]|reject[6] ADDR[/MASK][:PORT]". If /MASK is omitted then
           this policy just applies to the host given. Instead of giving a
           host or network you can also use "*" to denote the universe
           (0.0.0.0/0 and ::/0), or *4 to denote all IPv4 addresses, and *6 to
           denote all IPv6 addresses.  PORT can be a single port number, an
           interval of ports "FROM_PORT-TO_PORT", or "*". If PORT is omitted,
           that means "*".


           For example, "accept 18.7.22.69:*,reject 18.0.0.0/8:*,accept *:*"
           would reject any IPv4 traffic destined for MIT except for
           web.mit.edu, and accept any other IPv4 or IPv6 traffic.


           Tor also allows IPv6 exit policy entries. For instance, "reject6
           [FC00::]/7:*" rejects all destinations that share 7 most
           significant bit prefix with address FC00::. Respectively, "accept6
           [C000::]/3:*" accepts all destinations that share 3 most
           significant bit prefix with address C000::.


           accept6 and reject6 only produce IPv6 exit policy entries. Using an
           IPv4 address with accept6 or reject6 is ignored and generates a
           warning. accept/reject allows either IPv4 or IPv6 addresses. Use *4
           as an IPv4 wildcard address, and *6 as an IPv6 wildcard address.
           accept/reject * expands to matching IPv4 and IPv6 wildcard address
           rules.


           To specify all IPv4 and IPv6 internal and link-local networks
           (including 0.0.0.0/8, 169.254.0.0/16, 127.0.0.0/8, 192.168.0.0/16,
           10.0.0.0/8, 172.16.0.0/12, [::]/8, [FC00::]/7, [FE80::]/10,
           [FEC0::]/10, [FF00::]/8, and [::]/127), you can use the "private"
           alias instead of an address. ("private" always produces rules for
           IPv4 and IPv6 addresses, even when used with accept6/reject6.)


           Private addresses are rejected by default (at the beginning of your
           exit policy), along with any configured primary public IPv4 and
           IPv6 addresses. These private addresses are rejected unless you set
           the ExitPolicyRejectPrivate config option to 0. For example, once
           you’ve done that, you could allow HTTP to 127.0.0.1 and block all
           other connections to internal networks with "accept
           127.0.0.1:80,reject private:*", though that may also allow
           connections to your own computer that are addressed to its public
           (external) IP address. See RFC 1918 and RFC 3330 for more details
           about internal and reserved IP address space. See
           ExitPolicyRejectLocalInterfaces if you want to block every address
           on the relay, even those that aren’t advertised in the descriptor.


           This directive can be specified multiple times so you don’t have to
           put it all on one line.


           Policies are considered first to last, and the first match wins. If
           you want to allow the same ports on IPv4 and IPv6, write your rules
           using accept/reject *. If you want to allow different ports on IPv4
           and IPv6, write your IPv6 rules using accept6/reject6 *6, and your
           IPv4 rules using accept/reject *4. If you want to _replace_ the
           default exit policy, end your exit policy with either a reject *:*
           or an accept *:*. Otherwise, you’re _augmenting_ (prepending to)
           the default exit policy.


           If you want to use a reduced exit policy rather than the default
           exit policy, set "ReducedExitPolicy 1". If you want to replace the
           default exit policy with your custom exit policy, end your exit
           policy with either a reject : or an accept :. Otherwise, you’re
           augmenting (prepending to) the default or reduced exit policy.


           The default exit policy is:

               reject *:25
               reject *:119
               reject *:135-139
               reject *:445
               reject *:563
               reject *:1214
               reject *:4661-4666
               reject *:6346-6429
               reject *:6699
               reject *:6881-6999
               accept *:*

           Since the default exit policy uses accept/reject *, it applies to
           both IPv4 and IPv6 addresses.

       ExitPolicyRejectPrivate 0|1
           Reject all private (local) networks, along with the relay’s
           advertised public IPv4 and IPv6 addresses, at the beginning of your
           exit policy. See above entry on ExitPolicy. (Default: 1)

       ExitPolicyRejectLocalInterfaces 0|1
           Reject all IPv4 and IPv6 addresses that the relay knows about, at
           the beginning of your exit policy. This includes any
           OutboundBindAddress, the bind addresses of any port options, such
           as ControlPort or DNSPort, and any public IPv4 and IPv6 addresses
           on any interface on the relay. (If IPv6Exit is not set, all IPv6
           addresses will be rejected anyway.) See above entry on ExitPolicy.
           This option is off by default, because it lists all public relay IP
           addresses in the ExitPolicy, even those relay operators might
           prefer not to disclose. (Default: 0)

       ReducedExitPolicy 0|1
           If set, use a reduced exit policy rather than the default one.


           The reduced exit policy is an alternative to the default exit
           policy. It allows as many Internet services as possible while still
           blocking the majority of TCP ports. Currently, the policy allows
           approximately 65 ports. This reduces the odds that your node will
           be used for peer-to-peer applications.


           The reduced exit policy is:

               accept *:20-21
               accept *:22
               accept *:23
               accept *:43
               accept *:53
               accept *:79
               accept *:80-81
               accept *:88
               accept *:110
               accept *:143
               accept *:194
               accept *:220
               accept *:389
               accept *:443
               accept *:464
               accept *:465
               accept *:531
               accept *:543-544
               accept *:554
               accept *:563
               accept *:587
               accept *:636
               accept *:706
               accept *:749
               accept *:873
               accept *:902-904
               accept *:981
               accept *:989-990
               accept *:991
               accept *:992
               accept *:993
               accept *:994
               accept *:995
               accept *:1194
               accept *:1220
               accept *:1293
               accept *:1500
               accept *:1533
               accept *:1677
               accept *:1723
               accept *:1755
               accept *:1863
               accept *:2082
               accept *:2083
               accept *:2086-2087
               accept *:2095-2096
               accept *:2102-2104
               accept *:3128
               accept *:3389
               accept *:3690
               accept *:4321
               accept *:4643
               accept *:5050
               accept *:5190
               accept *:5222-5223
               accept *:5228
               accept *:5900
               accept *:6660-6669
               accept *:6679
               accept *:6697
               accept *:8000
               accept *:8008
               accept *:8074
               accept *:8080
               accept *:8082
               accept *:8087-8088
               accept *:8232-8233
               accept *:8332-8333
               accept *:8443
               accept *:8888
               accept *:9418
               accept *:9999
               accept *:10000
               accept *:11371
               accept *:19294
               accept *:19638
               accept *:50002
               accept *:64738
               reject *:*

               (Default: 0)

       IPv6Exit 0|1
           If set, and we are an exit node, allow clients to use us for IPv6
           traffic. (Default: 0)

       MaxOnionQueueDelay NUM [msec|second]
           If we have more onionskins queued for processing than we can
           process in this amount of time, reject new ones. (Default: 1750
           msec)

       MyFamily fingerprint,fingerprint,...
           Declare that this Tor relay is controlled or administered by a
           group or organization identical or similar to that of the other
           relays, defined by their (possibly $-prefixed) identity
           fingerprints. This option can be repeated many times, for
           convenience in defining large families: all fingerprints in all
           MyFamily lines are merged into one list. When two relays both
           declare that they are in the same 'family', Tor clients will not
           use them in the same circuit. (Each relay only needs to list the
           other servers in its family; it doesn’t need to list itself, but it
           won’t hurt if it does.) Do not list any bridge relay as it would
           compromise its concealment.


           When listing a node, it’s better to list it by fingerprint than by
           nickname: fingerprints are more reliable.


           If you run more than one relay, the MyFamily option on each relay
           must list all other relays, as described above.


           Note: do not use MyFamily when configuring your Tor instance as a
           brigde.

       Nickname name
           Set the server’s nickname to 'name'. Nicknames must be between 1
           and 19 characters inclusive, and must contain only the characters
           [a-zA-Z0-9]. If not set, Unnamed will be used. Relays can always be
           uniquely identified by their identity fingerprints.

       NumCPUs num
           How many processes to use at once for decrypting onionskins and
           other parallelizable operations. If this is set to 0, Tor will try
           to detect how many CPUs you have, defaulting to 1 if it can’t tell.
           (Default: 0)

       ORPort [address:]PORT|auto [flags]
           Advertise this port to listen for connections from Tor clients and
           servers. This option is required to be a Tor server. Set it to
           "auto" to have Tor pick a port for you. Set it to 0 to not run an
           ORPort at all. This option can occur more than once. (Default: 0)


           Tor recognizes these flags on each ORPort:

           NoAdvertise
               By default, we bind to a port and tell our users about it. If
               NoAdvertise is specified, we don’t advertise, but listen
               anyway. This can be useful if the port everybody will be
               connecting to (for example, one that’s opened on our firewall)
               is somewhere else.

           NoListen
               By default, we bind to a port and tell our users about it. If
               NoListen is specified, we don’t bind, but advertise anyway.
               This can be useful if something else (for example, a firewall’s
               port forwarding configuration) is causing connections to reach
               us.

           IPv4Only
               If the address is absent, or resolves to both an IPv4 and an
               IPv6 address, only listen to the IPv4 address.

           IPv6Only
               If the address is absent, or resolves to both an IPv4 and an
               IPv6 address, only listen to the IPv6 address.

           For obvious reasons, NoAdvertise and NoListen are mutually
           exclusive, and IPv4Only and IPv6Only are mutually exclusive.

       PublishServerDescriptor 0|1|v3|bridge,...
           This option specifies which descriptors Tor will publish when
           acting as a relay. You can choose multiple arguments, separated by
           commas.


           If this option is set to 0, Tor will not publish its descriptors to
           any directories. (This is useful if you’re testing out your server,
           or if you’re using a Tor controller that handles directory
           publishing for you.) Otherwise, Tor will publish its descriptors of
           all type(s) specified. The default is "1", which means "if running
           as a relay or bridge, publish descriptors to the appropriate
           authorities". Other possibilities are "v3", meaning "publish as if
           you’re a relay", and "bridge", meaning "publish as if you’re a
           bridge".

       ShutdownWaitLength NUM
           When we get a SIGINT and we’re a server, we begin shutting down: we
           close listeners and start refusing new circuits. After NUM seconds,
           we exit. If we get a second SIGINT, we exit immediately. (Default:
           30 seconds)

       SSLKeyLifetime N minutes|hours|days|weeks
           When creating a link certificate for our outermost SSL handshake,
           set its lifetime to this amount of time. If set to 0, Tor will
           choose some reasonable random defaults. (Default: 0)

       HeartbeatPeriod N minutes|hours|days|weeks
           Log a heartbeat message every HeartbeatPeriod seconds. This is a
           log level notice message, designed to let you know your Tor server
           is still alive and doing useful things. Settings this to 0 will
           disable the heartbeat. Otherwise, it must be at least 30 minutes.
           (Default: 6 hours)

       MainloopStats 0|1
           Log main loop statistics every HeartbeatPeriod seconds. This is a
           log level notice message designed to help developers instrumenting
           Tor’s main event loop. (Default: 0)

       AccountingMax N
       bytes|KBytes|MBytes|GBytes|TBytes|KBits|MBits|GBits|TBits
           Limits the max number of bytes sent and received within a set time
           period using a given calculation rule (see: AccountingStart,
           AccountingRule). Useful if you need to stay under a specific
           bandwidth. By default, the number used for calculation is the max
           of either the bytes sent or received. For example, with
           AccountingMax set to 1 GByte, a server could send 900 MBytes and
           receive 800 MBytes and continue running. It will only hibernate
           once one of the two reaches 1 GByte. This can be changed to use the
           sum of the both bytes received and sent by setting the
           AccountingRule option to "sum" (total bandwidth in/out). When the
           number of bytes remaining gets low, Tor will stop accepting new
           connections and circuits. When the number of bytes is exhausted,
           Tor will hibernate until some time in the next accounting period.
           To prevent all servers from waking at the same time, Tor will also
           wait until a random point in each period before waking up. If you
           have bandwidth cost issues, enabling hibernation is preferable to
           setting a low bandwidth, since it provides users with a collection
           of fast servers that are up some of the time, which is more useful
           than a set of slow servers that are always "available".

       AccountingRule sum|max|in|out
           How we determine when our AccountingMax has been reached (when we
           should hibernate) during a time interval. Set to "max" to calculate
           using the higher of either the sent or received bytes (this is the
           default functionality). Set to "sum" to calculate using the sent
           plus received bytes. Set to "in" to calculate using only the
           received bytes. Set to "out" to calculate using only the sent
           bytes. (Default: max)

       AccountingStart day|week|month [day] HH:MM
           Specify how long accounting periods last. If month is given, each
           accounting period runs from the time HH:MM on the dayth day of one
           month to the same day and time of the next. The relay will go at
           full speed, use all the quota you specify, then hibernate for the
           rest of the period. (The day must be between 1 and 28.) If week is
           given, each accounting period runs from the time HH:MM of the dayth
           day of one week to the same day and time of the next week, with
           Monday as day 1 and Sunday as day 7. If day is given, each
           accounting period runs from the time HH:MM each day to the same
           time on the next day. All times are local, and given in 24-hour
           time. (Default: "month 1 0:00")

       RefuseUnknownExits 0|1|auto
           Prevent nodes that don’t appear in the consensus from exiting using
           this relay. If the option is 1, we always block exit attempts from
           such nodes; if it’s 0, we never do, and if the option is "auto",
           then we do whatever the authorities suggest in the consensus (and
           block if the consensus is quiet on the issue). (Default: auto)

       ServerDNSResolvConfFile filename
           Overrides the default DNS configuration with the configuration in
           filename. The file format is the same as the standard Unix
           "resolv.conf" file (7). This option, like all other ServerDNS
           options, only affects name lookups that your server does on behalf
           of clients. (Defaults to use the system DNS configuration.)

       ServerDNSAllowBrokenConfig 0|1
           If this option is false, Tor exits immediately if there are
           problems parsing the system DNS configuration or connecting to
           nameservers. Otherwise, Tor continues to periodically retry the
           system nameservers until it eventually succeeds. (Default: 1)

       ServerDNSSearchDomains 0|1
           If set to 1, then we will search for addresses in the local search
           domain. For example, if this system is configured to believe it is
           in "example.com", and a client tries to connect to "www", the
           client will be connected to "www.example.com". This option only
           affects name lookups that your server does on behalf of clients.
           (Default: 0)

       ServerDNSDetectHijacking 0|1
           When this option is set to 1, we will test periodically to
           determine whether our local nameservers have been configured to
           hijack failing DNS requests (usually to an advertising site). If
           they are, we will attempt to correct this. This option only affects
           name lookups that your server does on behalf of clients. (Default:
           1)

       ServerDNSTestAddresses hostname,hostname,...
           When we’re detecting DNS hijacking, make sure that these valid
           addresses aren’t getting redirected. If they are, then our DNS is
           completely useless, and we’ll reset our exit policy to "reject
           *:*". This option only affects name lookups that your server does
           on behalf of clients. (Default: "www.google.com, www.mit.edu,
           www.yahoo.com, www.slashdot.org")

       ServerDNSAllowNonRFC953Hostnames 0|1
           When this option is disabled, Tor does not try to resolve hostnames
           containing illegal characters (like @ and :) rather than sending
           them to an exit node to be resolved. This helps trap accidental
           attempts to resolve URLs and so on. This option only affects name
           lookups that your server does on behalf of clients. (Default: 0)

       BridgeRecordUsageByCountry 0|1
           When this option is enabled and BridgeRelay is also enabled, and we
           have GeoIP data, Tor keeps a per-country count of how many client
           addresses have contacted it so that it can help the bridge
           authority guess which countries have blocked access to it.
           (Default: 1)

       ServerDNSRandomizeCase 0|1
           When this option is set, Tor sets the case of each character
           randomly in outgoing DNS requests, and makes sure that the case
           matches in DNS replies. This so-called "0x20 hack" helps resist
           some types of DNS poisoning attack. For more information, see
           "Increased DNS Forgery Resistance through 0x20-Bit Encoding". This
           option only affects name lookups that your server does on behalf of
           clients. (Default: 1)

       GeoIPFile filename
           A filename containing IPv4 GeoIP data, for use with by-country
           statistics.

       GeoIPv6File filename
           A filename containing IPv6 GeoIP data, for use with by-country
           statistics.

       CellStatistics 0|1
           Relays only. When this option is enabled, Tor collects statistics
           about cell processing (i.e. mean time a cell is spending in a
           queue, mean number of cells in a queue and mean number of processed
           cells per circuit) and writes them into disk every 24 hours. Onion
           router operators may use the statistics for performance monitoring.
           If ExtraInfoStatistics is enabled, it will published as part of
           extra-info document. (Default: 0)

       PaddingStatistics 0|1
           Relays only. When this option is enabled, Tor collects statistics
           for padding cells sent and received by this relay, in addition to
           total cell counts. These statistics are rounded, and omitted if
           traffic is low. This information is important for load balancing
           decisions related to padding. If ExtraInfoStatistics is enabled, it
           will be published as a part of extra-info document. (Default: 1)

       DirReqStatistics 0|1
           Relays and bridges only. When this option is enabled, a Tor
           directory writes statistics on the number and response time of
           network status requests to disk every 24 hours. Enables relay and
           bridge operators to monitor how much their server is being used by
           clients to learn about Tor network. If ExtraInfoStatistics is
           enabled, it will published as part of extra-info document.
           (Default: 1)

       EntryStatistics 0|1
           Relays only. When this option is enabled, Tor writes statistics on
           the number of directly connecting clients to disk every 24 hours.
           Enables relay operators to monitor how much inbound traffic that
           originates from Tor clients passes through their server to go
           further down the Tor network. If ExtraInfoStatistics is enabled, it
           will be published as part of extra-info document. (Default: 0)

       ExitPortStatistics 0|1
           Exit relays only. When this option is enabled, Tor writes
           statistics on the number of relayed bytes and opened stream per
           exit port to disk every 24 hours. Enables exit relay operators to
           measure and monitor amounts of traffic that leaves Tor network
           through their exit node. If ExtraInfoStatistics is enabled, it will
           be published as part of extra-info document. (Default: 0)

       ConnDirectionStatistics 0|1
           Relays only. When this option is enabled, Tor writes statistics on
           the amounts of traffic it passes between itself and other relays to
           disk every 24 hours. Enables relay operators to monitor how much
           their relay is being used as middle node in the circuit. If
           ExtraInfoStatistics is enabled, it will be published as part of
           extra-info document. (Default: 0)

       HiddenServiceStatistics 0|1
           Relays only. When this option is enabled, a Tor relay writes
           obfuscated statistics on its role as hidden-service directory,
           introduction point, or rendezvous point to disk every 24 hours. If
           ExtraInfoStatistics is also enabled, these statistics are further
           published to the directory authorities. (Default: 1)

       ExtraInfoStatistics 0|1
           When this option is enabled, Tor includes previously gathered
           statistics in its extra-info documents that it uploads to the
           directory authorities. (Default: 1)

       ExtendAllowPrivateAddresses 0|1
           When this option is enabled, Tor will connect to relays on
           localhost, RFC1918 addresses, and so on. In particular, Tor will
           make direct OR connections, and Tor routers allow EXTEND requests,
           to these private addresses. (Tor will always allow connections to
           bridges, proxies, and pluggable transports configured on private
           addresses.) Enabling this option can create security issues; you
           should probably leave it off. (Default: 0)

       MaxMemInQueues N bytes|KB|MB|GB
           This option configures a threshold above which Tor will assume that
           it needs to stop queueing or buffering data because it’s about to
           run out of memory. If it hits this threshold, it will begin killing
           circuits until it has recovered at least 10% of this memory. Do not
           set this option too low, or your relay may be unreliable under
           load. This option only affects some queues, so the actual process
           size will be larger than this. If this option is set to 0, Tor will
           try to pick a reasonable default based on your system’s physical
           memory. (Default: 0)

       DisableOOSCheck 0|1
           This option disables the code that closes connections when Tor
           notices that it is running low on sockets. Right now, it is on by
           default, since the existing out-of-sockets mechanism tends to kill
           OR connections more than it should. (Default: 1)

       SigningKeyLifetime N days|weeks|months
           For how long should each Ed25519 signing key be valid? Tor uses a
           permanent master identity key that can be kept offline, and
           periodically generates new "signing" keys that it uses online. This
           option configures their lifetime. (Default: 30 days)

       OfflineMasterKey 0|1
           If non-zero, the Tor relay will never generate or load its master
           secret key. Instead, you’ll have to use "tor --keygen" to manage
           the permanent ed25519 master identity key, as well as the
           corresponding temporary signing keys and certificates. (Default: 0)

       KeyDirectory DIR
           Store secret keys in DIR. Can not be changed while tor is running.
           (Default: the "keys" subdirectory of DataDirectory.)

       KeyDirectoryGroupReadable 0|1
           If this option is set to 0, don’t allow the filesystem group to
           read the KeywDirectory. If the option is set to 1, make the
           KeyDirectory readable by the default GID. (Default: 0)

       RephistTrackTime N seconds|minutes|hours|days|weeks
           Tells an authority, or other node tracking node reliability and
           history, that fine-grained information about nodes can be discarded
           when it hasn’t changed for a given amount of time. (Default: 24
           hours)

DIRECTORY SERVER OPTIONS
       The following options are useful only for directory servers. (Relays
       with enough bandwidth automatically become directory servers; see
       DirCache for details.)

       DirPortFrontPage FILENAME
           When this option is set, it takes an HTML file and publishes it as
           "/" on the DirPort. Now relay operators can provide a disclaimer
           without needing to set up a separate webserver. There’s a sample
           disclaimer in contrib/operator-tools/tor-exit-notice.html.

       DirPort [address:]PORT|auto [flags]
           If this option is nonzero, advertise the directory service on this
           port. Set it to "auto" to have Tor pick a port for you. This option
           can occur more than once, but only one advertised DirPort is
           supported: all but one DirPort must have the NoAdvertise flag set.
           (Default: 0)


           The same flags are supported here as are supported by ORPort.

       DirPolicy policy,policy,...
           Set an entrance policy for this server, to limit who can connect to
           the directory ports. The policies have the same form as exit
           policies above, except that port specifiers are ignored. Any
           address not matched by some entry in the policy is accepted.

       DirCache 0|1
           When this option is set, Tor caches all current directory documents
           except extra info documents, and accepts client requests for them.
           If DownloadExtraInfo is set, cached extra info documents are also
           cached. Setting DirPort is not required for DirCache, because
           clients connect via the ORPort by default. Setting either DirPort
           or BridgeRelay and setting DirCache to 0 is not supported.
           (Default: 1)

       MaxConsensusAgeForDiffs N minutes|hours|days|weeks
           When this option is nonzero, Tor caches will not try to generate
           consensus diffs for any consensus older than this amount of time.
           If this option is set to zero, Tor will pick a reasonable default
           from the current networkstatus document. You should not set this
           option unless your cache is severely low on disk space or CPU. If
           you need to set it, keeping it above 3 or 4 hours will help clients
           much more than setting it to zero. (Default: 0)

DENIAL OF SERVICE MITIGATION OPTIONS
       Tor has three built-in mitigation options that can be individually
       enabled/disabled and fine-tuned, but by default Tor directory
       authorities will define reasonable values for relays and no explicit
       configuration is required to make use of these protections. The
       mitigations take place at relays, and are as follows:

        1. If a single client address makes too many concurrent connections
           (this is configurable via DoSConnectionMaxConcurrentCount), hang up
           on further connections.

        2. If a single client IP address (v4 or v6) makes circuits too quickly
           (default values are more than 3 per second, with an allowed burst
           of 90, see DoSCircuitCreationRate and DoSCircuitCreationBurst)
           while also having too many connections open (default is 3, see
           DoSCircuitCreationMinConnections), tor will refuse any new circuit
           (CREATE cells) for the next while (random value between 1 and 2
           hours).

        3. If a client asks to establish a rendezvous point to you directly
           (ex: Tor2Web client), ignore the request.

       These defenses can be manually controlled by torrc options, but relays
       will also take guidance from consensus parameters using these same
       names, so there’s no need to configure anything manually. In doubt, do
       not change those values.

       The values set by the consensus, if any, can be found here:
       https://consensus-health.torproject.org/#consensusparams

       If any of the DoS mitigations are enabled, a heartbeat message will
       appear in your log at NOTICE level which looks like:

           DoS mitigation since startup: 429042 circuits rejected, 17 marked addresses.
           2238 connections closed. 8052 single hop clients refused.

       The following options are useful only for a public relay. They control
       the Denial of Service mitigation subsystem described above.

       DoSCircuitCreationEnabled 0|1|auto
           Enable circuit creation DoS mitigation. If set to 1 (enabled), tor
           will cache client IPs along with statistics in order to detect
           circuit DoS attacks. If an address is positively identified, tor
           will activate defenses against the address. See the
           DoSCircuitCreationDefenseType option for more details. This is a
           client to relay detection only. "auto" means use the consensus
           parameter. If not defined in the consensus, the value is 0.
           (Default: auto)

       DoSCircuitCreationMinConnections NUM
           Minimum threshold of concurrent connections before a client address
           can be flagged as executing a circuit creation DoS. In other words,
           once a client address reaches the circuit rate and has a minimum of
           NUM concurrent connections, a detection is positive. "0" means use
           the consensus parameter. If not defined in the consensus, the value
           is 3. (Default: 0)

       DoSCircuitCreationRate NUM
           The allowed circuit creation rate per second applied per client IP
           address. If this option is 0, it obeys a consensus parameter. If
           not defined in the consensus, the value is 3. (Default: 0)

       DoSCircuitCreationBurst NUM
           The allowed circuit creation burst per client IP address. If the
           circuit rate and the burst are reached, a client is marked as
           executing a circuit creation DoS. "0" means use the consensus
           parameter. If not defined in the consensus, the value is 90.
           (Default: 0)

       DoSCircuitCreationDefenseType NUM
           This is the type of defense applied to a detected client address.
           The possible values are:

           1: No defense.

           2: Refuse circuit creation for the
           DoSCircuitCreationDefenseTimePeriod period of time.

           "0" means use the consensus parameter. If not defined in the
           consensus, the value is 2. (Default: 0)

       DoSCircuitCreationDefenseTimePeriod N seconds|minutes|hours
           The base time period in seconds that the DoS defense is activated
           for. The actual value is selected randomly for each activation from
           N+1 to 3/2 * N. "0" means use the consensus parameter. If not
           defined in the consensus, the value is 3600 seconds (1 hour).
           (Default: 0)

       DoSConnectionEnabled 0|1|auto
           Enable the connection DoS mitigation. If set to 1 (enabled), for
           client address only, this allows tor to mitigate against large
           number of concurrent connections made by a single IP address.
           "auto" means use the consensus parameter. If not defined in the
           consensus, the value is 0. (Default: auto)

       DoSConnectionMaxConcurrentCount NUM
           The maximum threshold of concurrent connection from a client IP
           address. Above this limit, a defense selected by
           DoSConnectionDefenseType is applied. "0" means use the consensus
           parameter. If not defined in the consensus, the value is 100.
           (Default: 0)

       DoSConnectionDefenseType NUM
           This is the type of defense applied to a detected client address
           for the connection mitigation. The possible values are:

           1: No defense.

           2: Immediately close new connections.

           "0" means use the consensus parameter. If not defined in the
           consensus, the value is 2. (Default: 0)

       DoSRefuseSingleHopClientRendezvous 0|1|auto
           Refuse establishment of rendezvous points for single hop clients.
           In other words, if a client directly connects to the relay and
           sends an ESTABLISH_RENDEZVOUS cell, it is silently dropped. "auto"
           means use the consensus parameter. If not defined in the consensus,
           the value is 0. (Default: auto)

DIRECTORY AUTHORITY SERVER OPTIONS
       The following options enable operation as a directory authority, and
       control how Tor behaves as a directory authority. You should not need
       to adjust any of them if you’re running a regular relay or exit server
       on the public Tor network.

       AuthoritativeDirectory 0|1
           When this option is set to 1, Tor operates as an authoritative
           directory server. Instead of caching the directory, it generates
           its own list of good servers, signs it, and sends that to the
           clients. Unless the clients already have you listed as a trusted
           directory, you probably do not want to set this option.

       V3AuthoritativeDirectory 0|1
           When this option is set in addition to AuthoritativeDirectory, Tor
           generates version 3 network statuses and serves descriptors, etc as
           described in dir-spec.txt file of torspec (for Tor clients and
           servers running at least 0.2.0.x).

       VersioningAuthoritativeDirectory 0|1
           When this option is set to 1, Tor adds information on which
           versions of Tor are still believed safe for use to the published
           directory. Each version 1 authority is automatically a versioning
           authority; version 2 authorities provide this service optionally.
           See RecommendedVersions, RecommendedClientVersions, and
           RecommendedServerVersions.

       RecommendedVersions STRING
           STRING is a comma-separated list of Tor versions currently believed
           to be safe. The list is included in each directory, and nodes which
           pull down the directory learn whether they need to upgrade. This
           option can appear multiple times: the values from multiple lines
           are spliced together. When this is set then
           VersioningAuthoritativeDirectory should be set too.

       RecommendedPackages PACKAGENAME VERSION URL DIGESTTYPE=DIGEST
           Adds "package" line to the directory authority’s vote. This
           information is used to vote on the correct URL and digest for the
           released versions of different Tor-related packages, so that the
           consensus can certify them. This line may appear any number of
           times.

       RecommendedClientVersions STRING
           STRING is a comma-separated list of Tor versions currently believed
           to be safe for clients to use. This information is included in
           version 2 directories. If this is not set then the value of
           RecommendedVersions is used. When this is set then
           VersioningAuthoritativeDirectory should be set too.

       BridgeAuthoritativeDir 0|1
           When this option is set in addition to AuthoritativeDirectory, Tor
           accepts and serves server descriptors, but it caches and serves the
           main networkstatus documents rather than generating its own.
           (Default: 0)

       MinUptimeHidServDirectoryV2 N seconds|minutes|hours|days|weeks
           Minimum uptime of a v2 hidden service directory to be accepted as
           such by authoritative directories. (Default: 25 hours)

       RecommendedServerVersions STRING
           STRING is a comma-separated list of Tor versions currently believed
           to be safe for servers to use. This information is included in
           version 2 directories. If this is not set then the value of
           RecommendedVersions is used. When this is set then
           VersioningAuthoritativeDirectory should be set too.

       ConsensusParams STRING
           STRING is a space-separated list of key=value pairs that Tor will
           include in the "params" line of its networkstatus vote.

       DirAllowPrivateAddresses 0|1
           If set to 1, Tor will accept server descriptors with arbitrary
           "Address" elements. Otherwise, if the address is not an IP address
           or is a private IP address, it will reject the server descriptor.
           Additionally, Tor will allow exit policies for private networks to
           fulfill Exit flag requirements. (Default: 0)

       AuthDirBadExit AddressPattern...
           Authoritative directories only. A set of address patterns for
           servers that will be listed as bad exits in any network status
           document this authority publishes, if AuthDirListBadExits is set.


           (The address pattern syntax here and in the options below is the
           same as for exit policies, except that you don’t need to say
           "accept" or "reject", and ports are not needed.)

       AuthDirInvalid AddressPattern...
           Authoritative directories only. A set of address patterns for
           servers that will never be listed as "valid" in any network status
           document that this authority publishes.

       AuthDirReject AddressPattern...
           Authoritative directories only. A set of address patterns for
           servers that will never be listed at all in any network status
           document that this authority publishes, or accepted as an OR
           address in any descriptor submitted for publication by this
           authority.

       AuthDirBadExitCCs CC,...

       AuthDirInvalidCCs CC,...

       AuthDirRejectCCs CC,...
           Authoritative directories only. These options contain a
           comma-separated list of country codes such that any server in one
           of those country codes will be marked as a bad exit/invalid for
           use, or rejected entirely.

       AuthDirListBadExits 0|1
           Authoritative directories only. If set to 1, this directory has
           some opinion about which nodes are unsuitable as exit nodes. (Do
           not set this to 1 unless you plan to list non-functioning exits as
           bad; otherwise, you are effectively voting in favor of every
           declared exit as an exit.)

       AuthDirMaxServersPerAddr NUM
           Authoritative directories only. The maximum number of servers that
           we will list as acceptable on a single IP address. Set this to "0"
           for "no limit". (Default: 2)

       AuthDirFastGuarantee N
       bytes|KBytes|MBytes|GBytes|TBytes|KBits|MBits|GBits|TBits
           Authoritative directories only. If non-zero, always vote the Fast
           flag for any relay advertising this amount of capacity or more.
           (Default: 100 KBytes)

       AuthDirGuardBWGuarantee N
       bytes|KBytes|MBytes|GBytes|TBytes|KBits|MBits|GBits|TBits
           Authoritative directories only. If non-zero, this advertised
           capacity or more is always sufficient to satisfy the bandwidth
           requirement for the Guard flag. (Default: 2 MBytes)

       AuthDirPinKeys 0|1
           Authoritative directories only. If non-zero, do not allow any relay
           to publish a descriptor if any other relay has reserved its
           <Ed25519,RSA> identity keypair. In all cases, Tor records every
           keypair it accepts in a journal if it is new, or if it differs from
           the most recently accepted pinning for one of the keys it contains.
           (Default: 1)

       AuthDirSharedRandomness 0|1
           Authoritative directories only. Switch for the shared random
           protocol. If zero, the authority won’t participate in the protocol.
           If non-zero (default), the flag "shared-rand-participate" is added
           to the authority vote indicating participation in the protocol.
           (Default: 1)

       AuthDirTestEd25519LinkKeys 0|1
           Authoritative directories only. If this option is set to 0, then we
           treat relays as "Running" if their RSA key is correct when we probe
           them, regardless of their Ed25519 key. We should only ever set this
           option to 0 if there is some major bug in Ed25519 link
           authentication that causes us to label all the relays as not
           Running. (Default: 1)

       BridgePassword Password
           If set, contains an HTTP authenticator that tells a bridge
           authority to serve all requested bridge information. Used by the
           (only partially implemented) "bridge community" design, where a
           community of bridge relay operators all use an alternate bridge
           directory authority, and their target user audience can
           periodically fetch the list of available community bridges to stay
           up-to-date. (Default: not set)

       V3AuthVotingInterval N minutes|hours
           V3 authoritative directories only. Configures the server’s
           preferred voting interval. Note that voting will actually happen at
           an interval chosen by consensus from all the authorities' preferred
           intervals. This time SHOULD divide evenly into a day. (Default: 1
           hour)

       V3AuthVoteDelay N minutes|hours
           V3 authoritative directories only. Configures the server’s
           preferred delay between publishing its vote and assuming it has all
           the votes from all the other authorities. Note that the actual time
           used is not the server’s preferred time, but the consensus of all
           preferences. (Default: 5 minutes)

       V3AuthDistDelay N minutes|hours
           V3 authoritative directories only. Configures the server’s
           preferred delay between publishing its consensus and signature and
           assuming it has all the signatures from all the other authorities.
           Note that the actual time used is not the server’s preferred time,
           but the consensus of all preferences. (Default: 5 minutes)

       V3AuthNIntervalsValid NUM
           V3 authoritative directories only. Configures the number of
           VotingIntervals for which each consensus should be valid for.
           Choosing high numbers increases network partitioning risks;
           choosing low numbers increases directory traffic. Note that the
           actual number of intervals used is not the server’s preferred
           number, but the consensus of all preferences. Must be at least 2.
           (Default: 3)

       V3BandwidthsFile FILENAME
           V3 authoritative directories only. Configures the location of the
           bandwidth-authority generated file storing information on relays'
           measured bandwidth capacities. To avoid inconsistent reads,
           bandwidth data should be written to temporary file, then renamed to
           the configured filename. (Default: unset)

       V3AuthUseLegacyKey 0|1
           If set, the directory authority will sign consensuses not only with
           its own signing key, but also with a "legacy" key and certificate
           with a different identity. This feature is used to migrate
           directory authority keys in the event of a compromise. (Default: 0)

       AuthDirHasIPv6Connectivity 0|1
           Authoritative directories only. When set to 0, OR ports with an
           IPv6 address are not included in the authority’s votes. When set to
           1, IPv6 OR ports are tested for reachability like IPv4 OR ports. If
           the reachability test succeeds, the authority votes for the IPv6
           ORPort, and votes Running for the relay. If the reachability test
           fails, the authority does not vote for the IPv6 ORPort, and does
           not vote Running (Default: 0)


               The content of the consensus depends on the number of voting authorities
               that set AuthDirHasIPv6Connectivity:

               If no authorities set AuthDirHasIPv6Connectivity 1, there will be no
               IPv6 ORPorts in the consensus.

               If a minority of authorities set AuthDirHasIPv6Connectivity 1,
               unreachable IPv6 ORPorts will be removed from the consensus. But the
               majority of IPv4-only authorities will still vote the relay as Running.
               Reachable IPv6 ORPort lines will be included in the consensus

               If a majority of voting authorities set AuthDirHasIPv6Connectivity 1,
               relays with unreachable IPv6 ORPorts will not be listed as Running.
               Reachable IPv6 ORPort lines will be included in the consensus
               (To ensure that any valid majority will vote relays with unreachable
               IPv6 ORPorts not Running, 75% of authorities must set
               AuthDirHasIPv6Connectivity 1.)

       MinMeasuredBWsForAuthToIgnoreAdvertised N
           A total value, in abstract bandwidth units, describing how much
           measured total bandwidth an authority should have observed on the
           network before it will treat advertised bandwidths as wholly
           unreliable. (Default: 500)

HIDDEN SERVICE OPTIONS
       The following options are used to configure a hidden service.

       HiddenServiceDir DIRECTORY
           Store data files for a hidden service in DIRECTORY. Every hidden
           service must have a separate directory. You may use this option
           multiple times to specify multiple services. If DIRECTORY does not
           exist, Tor will create it. (Note: in current versions of Tor, if
           DIRECTORY is a relative path, it will be relative to the current
           working directory of Tor instance, not to its DataDirectory. Do not
           rely on this behavior; it is not guaranteed to remain the same in
           future versions.)

       HiddenServicePort VIRTPORT [TARGET]
           Configure a virtual port VIRTPORT for a hidden service. You may use
           this option multiple times; each time applies to the service using
           the most recent HiddenServiceDir. By default, this option maps the
           virtual port to the same port on 127.0.0.1 over TCP. You may
           override the target port, address, or both by specifying a target
           of addr, port, addr:port, or unix:path. (You can specify an IPv6
           target as [addr]:port. Unix paths may be quoted, and may use
           standard C escapes.) You may also have multiple lines with the same
           VIRTPORT: when a user connects to that VIRTPORT, one of the TARGETs
           from those lines will be chosen at random. Note that address-port
           pairs have to be comma-separated.

       PublishHidServDescriptors 0|1
           If set to 0, Tor will run any hidden services you configure, but it
           won’t advertise them to the rendezvous directory. This option is
           only useful if you’re using a Tor controller that handles hidserv
           publishing for you. (Default: 1)

       HiddenServiceVersion 2|3
           A list of rendezvous service descriptor versions to publish for the
           hidden service. Currently, versions 2 and 3 are supported.
           (Default: 3)

       HiddenServiceAuthorizeClient auth-type client-name,client-name,...
           If configured, the hidden service is accessible for authorized
           clients only. The auth-type can either be 'basic' for a
           general-purpose authorization protocol or 'stealth' for a less
           scalable protocol that also hides service activity from
           unauthorized clients. Only clients that are listed here are
           authorized to access the hidden service. Valid client names are 1
           to 16 characters long and only use characters in A-Za-z0-9+-_ (no
           spaces). If this option is set, the hidden service is not
           accessible for clients without authorization any more. Generated
           authorization data can be found in the hostname file. Clients need
           to put this authorization data in their configuration file using
           HidServAuth. This option is only for v2 services; v3 services
           configure client authentication in a subdirectory of
           HiddenServiceDir instead (see the Client Authorization section).

       HiddenServiceAllowUnknownPorts 0|1
           If set to 1, then connections to unrecognized ports do not cause
           the current hidden service to close rendezvous circuits. (Setting
           this to 0 is not an authorization mechanism; it is instead meant to
           be a mild inconvenience to port-scanners.) (Default: 0)

       HiddenServiceExportCircuitID protocol
           The onion service will use the given protocol to expose the global
           circuit identifier of each inbound client circuit via the selected
           protocol. The only protocol supported right now 'haproxy'. This
           option is only for v3 services. (Default: none)


           The haproxy option works in the following way: when the feature is
           enabled, the Tor process will write a header line when a client is
           connecting to the onion service. The header will look like this:


           "PROXY TCP6 fc00:dead:beef:4dad::ffff:ffff ::1 65535 42\r\n"


           We encode the "global circuit identifier" as the last 32-bits of
           the first IPv6 address. All other values in the header can safely
           be ignored. You can compute the global circuit identifier using the
           following formula given the IPv6 address
           "fc00:dead:beef:4dad::AABB:CCDD":


           global_circuit_id = (0xAA << 24) + (0xBB << 16) + (0xCC << 8) +
           0xDD;


           In the case above, where the last 32-bit is 0xffffffff, the global
           circuit identifier would be 4294967295. You can use this value
           together with Tor’s control port where it is possible to terminate
           a circuit given the global circuit identifier. For more information
           about this see controls-spec.txt.


           The HAProxy version 1 proxy protocol is described in detail at
           https://www.haproxy.org/download/1.8/doc/proxy-protocol.txt

       HiddenServiceMaxStreams N
           The maximum number of simultaneous streams (connections) per
           rendezvous circuit. The maximum value allowed is 65535. (Setting
           this to 0 will allow an unlimited number of simultaneous streams.)
           (Default: 0)

       HiddenServiceMaxStreamsCloseCircuit 0|1
           If set to 1, then exceeding HiddenServiceMaxStreams will cause the
           offending rendezvous circuit to be torn down, as opposed to stream
           creation requests that exceed the limit being silently ignored.
           (Default: 0)

       RendPostPeriod N seconds|minutes|hours|days|weeks
           Every time the specified period elapses, Tor uploads any rendezvous
           service descriptors to the directory servers. This information is
           also uploaded whenever it changes. Minimum value allowed is 10
           minutes and maximum is 3.5 days. This option is only for v2
           services. (Default: 1 hour)

       HiddenServiceDirGroupReadable 0|1
           If this option is set to 1, allow the filesystem group to read the
           hidden service directory and hostname file. If the option is set to
           0, only owner is able to read the hidden service directory.
           (Default: 0) Has no effect on Windows.

       HiddenServiceNumIntroductionPoints NUM
           Number of introduction points the hidden service will have. You
           can’t have more than 10 for v2 service and 20 for v3. (Default: 3)

       HiddenServiceSingleHopMode 0|1
           Experimental - Non Anonymous Hidden Services on a tor instance in
           HiddenServiceSingleHopMode make one-hop (direct) circuits between
           the onion service server, and the introduction and rendezvous
           points. (Onion service descriptors are still posted using 3-hop
           paths, to avoid onion service directories blocking the service.)
           This option makes every hidden service instance hosted by a tor
           instance a Single Onion Service. One-hop circuits make Single Onion
           servers easily locatable, but clients remain location-anonymous.
           However, the fact that a client is accessing a Single Onion rather
           than a Hidden Service may be statistically distinguishable.


           WARNING: Once a hidden service directory has been used by a tor
           instance in HiddenServiceSingleHopMode, it can NEVER be used again
           for a hidden service. It is best practice to create a new hidden
           service directory, key, and address for each new Single Onion
           Service and Hidden Service. It is not possible to run Single Onion
           Services and Hidden Services from the same tor instance: they
           should be run on different servers with different IP addresses.


           HiddenServiceSingleHopMode requires HiddenServiceNonAnonymousMode
           to be set to 1. Since a Single Onion service is non-anonymous, you
           can not configure a SOCKSPort on a tor instance that is running in
           HiddenServiceSingleHopMode. Can not be changed while tor is
           running. (Default: 0)

       HiddenServiceNonAnonymousMode 0|1
           Makes hidden services non-anonymous on this tor instance. Allows
           the non-anonymous HiddenServiceSingleHopMode. Enables direct
           connections in the server-side hidden service protocol. If you are
           using this option, you need to disable all client-side services on
           your Tor instance, including setting SOCKSPort to "0". Can not be
           changed while tor is running. (Default: 0)

CLIENT AUTHORIZATION
       (Version 3 only)

       To configure client authorization on the service side, the
       "<HiddenServiceDir>/authorized_clients/" directory needs to exist. Each
       file in that directory should be suffixed with ".auth" (i.e.
       "alice.auth"; the file name is irrelevant) and its content format MUST
       be:

           <auth-type>:<key-type>:<base32-encoded-public-key>

       The supported <auth-type> are: "descriptor". The supported <key-type>
       are: "x25519". The <base32-encoded-public-key> is the base32
       representation of the raw key bytes only (32 bytes for x25519).

       Each file MUST contain one line only. Any malformed file will be
       ignored. Client authorization will only be enabled for the service if
       tor successfully loads at least one authorization file.

       Note that once you’ve configured client authorization, anyone else with
       the address won’t be able to access it from this point on. If no
       authorization is configured, the service will be accessible to anyone
       with the onion address.

       Revoking a client can be done by removing their ".auth" file, however
       the revocation will be in effect only after the tor process gets
       restarted even if a SIGHUP takes place.

       See the Appendix G in the rend-spec-v3.txt file of torspec for more
       information.

TESTING NETWORK OPTIONS
       The following options are used for running a testing Tor network.

       TestingTorNetwork 0|1
           If set to 1, Tor adjusts default values of the configuration
           options below, so that it is easier to set up a testing Tor
           network. May only be set if non-default set of DirAuthorities is
           set. Cannot be unset while Tor is running. (Default: 0)


               ServerDNSAllowBrokenConfig 1
               DirAllowPrivateAddresses 1
               EnforceDistinctSubnets 0
               AssumeReachable 1
               AuthDirMaxServersPerAddr 0
               AuthDirMaxServersPerAuthAddr 0
               ClientBootstrapConsensusAuthorityDownloadInitialDelay 0
               ClientBootstrapConsensusFallbackDownloadInitialDelay 0
               ClientBootstrapConsensusAuthorityOnlyDownloadInitialDelay 0
               ClientDNSRejectInternalAddresses 0
               ClientRejectInternalAddresses 0
               CountPrivateBandwidth 1
               ExitPolicyRejectPrivate 0
               ExtendAllowPrivateAddresses 1
               V3AuthVotingInterval 5 minutes
               V3AuthVoteDelay 20 seconds
               V3AuthDistDelay 20 seconds
               MinUptimeHidServDirectoryV2 0 seconds
               TestingV3AuthInitialVotingInterval 5 minutes
               TestingV3AuthInitialVoteDelay 20 seconds
               TestingV3AuthInitialDistDelay 20 seconds
               TestingAuthDirTimeToLearnReachability 0 minutes
               TestingEstimatedDescriptorPropagationTime 0 minutes
               TestingServerDownloadInitialDelay 0
               TestingClientDownloadInitialDelay 0
               TestingServerConsensusDownloadInitialDelay 0
               TestingClientConsensusDownloadInitialDelay 0
               TestingBridgeDownloadInitialDelay 10
               TestingBridgeBootstrapDownloadInitialDelay 0
               TestingClientMaxIntervalWithoutRequest 5 seconds
               TestingDirConnectionMaxStall 30 seconds
               TestingEnableConnBwEvent 1
               TestingEnableCellStatsEvent 1

       TestingV3AuthInitialVotingInterval N minutes|hours
           Like V3AuthVotingInterval, but for initial voting interval before
           the first consensus has been created. Changing this requires that
           TestingTorNetwork is set. (Default: 30 minutes)

       TestingV3AuthInitialVoteDelay N minutes|hours
           Like V3AuthVoteDelay, but for initial voting interval before the
           first consensus has been created. Changing this requires that
           TestingTorNetwork is set. (Default: 5 minutes)

       TestingV3AuthInitialDistDelay N minutes|hours
           Like V3AuthDistDelay, but for initial voting interval before the
           first consensus has been created. Changing this requires that
           TestingTorNetwork is set. (Default: 5 minutes)

       TestingV3AuthVotingStartOffset N seconds|minutes|hours
           Directory authorities offset voting start time by this much.
           Changing this requires that TestingTorNetwork is set. (Default: 0)

       TestingAuthDirTimeToLearnReachability N minutes|hours
           After starting as an authority, do not make claims about whether
           routers are Running until this much time has passed. Changing this
           requires that TestingTorNetwork is set. (Default: 30 minutes)

       TestingEstimatedDescriptorPropagationTime N minutes|hours
           Clients try downloading server descriptors from directory caches
           after this time. Changing this requires that TestingTorNetwork is
           set. (Default: 10 minutes)

       TestingMinFastFlagThreshold N
       bytes|KBytes|MBytes|GBytes|TBytes|KBits|MBits|GBits|TBits
           Minimum value for the Fast flag. Overrides the ordinary minimum
           taken from the consensus when TestingTorNetwork is set. (Default:
           0.)

       TestingServerDownloadInitialDelay N
           Initial delay in seconds for when servers should download things in
           general. Changing this requires that TestingTorNetwork is set.
           (Default: 0)

       TestingClientDownloadInitialDelay N
           Initial delay in seconds for when clients should download things in
           general. Changing this requires that TestingTorNetwork is set.
           (Default: 0)

       TestingServerConsensusDownloadInitialDelay N
           Initial delay in seconds for when servers should download
           consensuses. Changing this requires that TestingTorNetwork is set.
           (Default: 0)

       TestingClientConsensusDownloadInitialDelay N
           Initial delay in seconds for when clients should download
           consensuses. Changing this requires that TestingTorNetwork is set.
           (Default: 0)

       TestingBridgeDownloadInitialDelay N
           Initial delay in seconds for when clients should download each
           bridge descriptor when they know that one or more of their
           configured bridges are running. Changing this requires that
           TestingTorNetwork is set. (Default: 10800)

       TestingBridgeBootstrapDownloadInitialDelay N
           Initial delay in seconds for when clients should download each
           bridge descriptor when they have just started, or when they can not
           contact any of their bridges. Changing this requires that
           TestingTorNetwork is set. (Default: 0)

       TestingClientMaxIntervalWithoutRequest N seconds|minutes
           When directory clients have only a few descriptors to request, they
           batch them until they have more, or until this amount of time has
           passed. Changing this requires that TestingTorNetwork is set.
           (Default: 10 minutes)

       TestingDirConnectionMaxStall N seconds|minutes
           Let a directory connection stall this long before expiring it.
           Changing this requires that TestingTorNetwork is set. (Default: 5
           minutes)

       TestingDirAuthVoteExit node,node,...
           A list of identity fingerprints, country codes, and address
           patterns of nodes to vote Exit for regardless of their uptime,
           bandwidth, or exit policy. See the ExcludeNodes option for more
           information on how to specify nodes.


           In order for this option to have any effect, TestingTorNetwork has
           to be set. See the ExcludeNodes option for more information on how
           to specify nodes.

       TestingDirAuthVoteExitIsStrict 0|1
           If True (1), a node will never receive the Exit flag unless it is
           specified in the TestingDirAuthVoteExit list, regardless of its
           uptime, bandwidth, or exit policy.


           In order for this option to have any effect, TestingTorNetwork has
           to be set.

       TestingDirAuthVoteGuard node,node,...
           A list of identity fingerprints and country codes and address
           patterns of nodes to vote Guard for regardless of their uptime and
           bandwidth. See the ExcludeNodes option for more information on how
           to specify nodes.


           In order for this option to have any effect, TestingTorNetwork has
           to be set.

       TestingDirAuthVoteGuardIsStrict 0|1
           If True (1), a node will never receive the Guard flag unless it is
           specified in the TestingDirAuthVoteGuard list, regardless of its
           uptime and bandwidth.


           In order for this option to have any effect, TestingTorNetwork has
           to be set.

       TestingDirAuthVoteHSDir node,node,...
           A list of identity fingerprints and country codes and address
           patterns of nodes to vote HSDir for regardless of their uptime and
           DirPort. See the ExcludeNodes option for more information on how to
           specify nodes.


           In order for this option to have any effect, TestingTorNetwork must
           be set.

       TestingDirAuthVoteHSDirIsStrict 0|1
           If True (1), a node will never receive the HSDir flag unless it is
           specified in the TestingDirAuthVoteHSDir list, regardless of its
           uptime and DirPort.


           In order for this option to have any effect, TestingTorNetwork has
           to be set.

       TestingEnableConnBwEvent 0|1
           If this option is set, then Tor controllers may register for
           CONN_BW events. Changing this requires that TestingTorNetwork is
           set. (Default: 0)

       TestingEnableCellStatsEvent 0|1
           If this option is set, then Tor controllers may register for
           CELL_STATS events. Changing this requires that TestingTorNetwork is
           set. (Default: 0)

       TestingMinExitFlagThreshold N
       KBytes|MBytes|GBytes|TBytes|KBits|MBits|GBits|TBits
           Sets a lower-bound for assigning an exit flag when running as an
           authority on a testing network. Overrides the usual default lower
           bound of 4 KB. (Default: 0)

       TestingLinkCertLifetime N seconds|minutes|hours|days|weeks|months
           Overrides the default lifetime for the certificates used to
           authenticate our X509 link cert with our ed25519 signing key.
           (Default: 2 days)

       TestingAuthKeyLifetime N seconds|minutes|hours|days|weeks|months
           Overrides the default lifetime for a signing Ed25519 TLS Link
           authentication key. (Default: 2 days)

       TestingLinkKeySlop N seconds|minutes|hours

       TestingAuthKeySlop N seconds|minutes|hours

       TestingSigningKeySlop N seconds|minutes|hours
           How early before the official expiration of a an Ed25519 signing
           key do we replace it and issue a new key? (Default: 3 hours for
           link and auth; 1 day for signing.)

NON-PERSISTENT OPTIONS
       These options are not saved to the torrc file by the "SAVECONF"
       controller command. Other options of this type are documented in
       control-spec.txt, section 5.4. End-users should mostly ignore them.

       __ControlPort, __DirPort, __DNSPort, __ExtORPort, __NATDPort, __ORPort,
       __SocksPort, \_\_TransPort
           These underscore-prefixed options are variants of the regular Port
           options. They behave the same, except they are not saved to the
           torrc file by the controller’s SAVECONF command.

SIGNALS
       Tor catches the following signals:

       SIGTERM
           Tor will catch this, clean up and sync to disk if necessary, and
           exit.

       SIGINT
           Tor clients behave as with SIGTERM; but Tor servers will do a
           controlled slow shutdown, closing listeners and waiting 30 seconds
           before exiting. (The delay can be configured with the
           ShutdownWaitLength config option.)

       SIGHUP
           The signal instructs Tor to reload its configuration (including
           closing and reopening logs), and kill and restart its helper
           processes if applicable.

       SIGUSR1
           Log statistics about current connections, past connections, and
           throughput.

       SIGUSR2
           Switch all logs to loglevel debug. You can go back to the old
           loglevels by sending a SIGHUP.

       SIGCHLD
           Tor receives this signal when one of its helper processes has
           exited, so it can clean up.

       SIGPIPE
           Tor catches this signal and ignores it.

       SIGXFSZ
           If this signal exists on your platform, Tor catches and ignores it.

FILES
       /etc/tor/torrc
           The configuration file, which contains "option value" pairs.

       $HOME/.torrc
           Fallback location for torrc, if /etc/tor/torrc is not found.

       /var/lib/tor/
           The tor process stores keys and other data here.

       CacheDirectory/cached-certs
           This file holds downloaded directory key certificates that are used
           to verify authenticity of documents generated by Tor directory
           authorities.

       CacheDirectory/cached-consensus and/or cached-microdesc-consensus
           The most recent consensus network status document we’ve downloaded.

       CacheDirectory/cached-descriptors and cached-descriptors.new
           These files hold downloaded router statuses. Some routers may
           appear more than once; if so, the most recently published
           descriptor is used. Lines beginning with @-signs are annotations
           that contain more information about a given router. The ".new" file
           is an append-only journal; when it gets too large, all entries are
           merged into a new cached-descriptors file.

       CacheDirectory/cached-extrainfo and cached-extrainfo.new
           As "cached-descriptors", but holds optionally-downloaded
           "extra-info" documents. Relays use these documents to send
           inessential information about statistics, bandwidth history, and
           network health to the authorities. They aren’t fetched by default;
           see the DownloadExtraInfo option for more info.

       CacheDirectory/cached-microdescs and cached-microdescs.new
           These files hold downloaded microdescriptors. Lines beginning with
           @-signs are annotations that contain more information about a given
           router. The ".new" file is an append-only journal; when it gets too
           large, all entries are merged into a new cached-microdescs file.

       CacheDirectory/cached-routers and cached-routers.new
           Obsolete versions of cached-descriptors and cached-descriptors.new.
           When Tor can’t find the newer files, it looks here instead.

       DataDirectory/state
           A set of persistent key-value mappings. These are documented in the
           file. These include:

           ·   The current entry guards and their status.

           ·   The current bandwidth accounting values.

           ·   When the file was last written

           ·   What version of Tor generated the state file

           ·   A short history of bandwidth usage, as produced in the server
               descriptors.

       DataDirectory/sr-state
           Authority only. State file used to record information about the
           current status of the shared-random-value voting state.

       CacheDirectory/diff-cache
           Directory cache only. Holds older consensuses, and diffs from older
           consensuses to the most recent consensus of each type, compressed
           in various ways. Each file contains a set of key-value arguments
           describing its contents, followed by a single NUL byte, followed by
           the main file contents.

       DataDirectory/bw_accounting
           Used to track bandwidth accounting values (when the current period
           starts and ends; how much has been read and written so far this
           period). This file is obsolete, and the data is now stored in the
           'state' file instead.

       DataDirectory/control_auth_cookie
           Used for cookie authentication with the controller. Location can be
           overridden by the CookieAuthFile config option. Regenerated on
           startup. See control-spec.txt in torspec for details. Only used
           when cookie authentication is enabled.

       DataDirectory/lock
           This file is used to prevent two Tor instances from using same data
           directory. If access to this file is locked, data directory is
           already in use by Tor.

       DataDirectory/key-pinning-journal
           Used by authorities. A line-based file that records mappings
           between RSA1024 identity keys and Ed25519 identity keys.
           Authorities enforce these mappings, so that once a relay has picked
           an Ed25519 key, stealing or factoring the RSA1024 key will no
           longer let an attacker impersonate the relay.

       KeyDirectory/authority_identity_key
           A v3 directory authority’s master identity key, used to
           authenticate its signing key. Tor doesn’t use this while it’s
           running. The tor-gencert program uses this. If you’re running an
           authority, you should keep this key offline, and not actually put
           it here.

       KeyDirectory/authority_certificate
           A v3 directory authority’s certificate, which authenticates the
           authority’s current vote- and consensus-signing key using its
           master identity key. Only directory authorities use this file.

       KeyDirectory/authority_signing_key
           A v3 directory authority’s signing key, used to sign votes and
           consensuses. Only directory authorities use this file. Corresponds
           to the authority_certificate cert.

       KeyDirectory/legacy_certificate
           As authority_certificate: used only when V3AuthUseLegacyKey is set.
           See documentation for V3AuthUseLegacyKey.

       KeyDirectory/legacy_signing_key
           As authority_signing_key: used only when V3AuthUseLegacyKey is set.
           See documentation for V3AuthUseLegacyKey.

       KeyDirectory/secret_id_key
           A relay’s RSA1024 permanent identity key, including private and
           public components. Used to sign router descriptors, and to sign
           other keys.

       KeyDirectory/ed25519_master_id_public_key
           The public part of a relay’s Ed25519 permanent identity key.

       KeyDirectory/ed25519_master_id_secret_key
           The private part of a relay’s Ed25519 permanent identity key. This
           key is used to sign the medium-term ed25519 signing key. This file
           can be kept offline, or kept encrypted. If so, Tor will not be able
           to generate new signing keys itself; you’ll need to use tor
           --keygen yourself to do so.

       KeyDirectory/ed25519_signing_secret_key
           The private and public components of a relay’s medium-term Ed25519
           signing key. This key is authenticated by the Ed25519 master key,
           in turn authenticates other keys (and router descriptors).

       KeyDirectory/ed25519_signing_cert
           The certificate which authenticates "ed25519_signing_secret_key" as
           having been signed by the Ed25519 master key.

       KeyDirectory/secret_onion_key and secret_onion_key.old
           A relay’s RSA1024 short-term onion key. Used to decrypt old-style
           ("TAP") circuit extension requests. The ".old" file holds the
           previously generated key, which the relay uses to handle any
           requests that were made by clients that didn’t have the new one.

       KeyDirectory/secret_onion_key_ntor and secret_onion_key_ntor.old
           A relay’s Curve25519 short-term onion key. Used to handle modern
           ("ntor") circuit extension requests. The ".old" file holds the
           previously generated key, which the relay uses to handle any
           requests that were made by clients that didn’t have the new one.

       DataDirectory/fingerprint
           Only used by servers. Holds the fingerprint of the server’s
           identity key.

       DataDirectory/hashed-fingerprint
           Only used by bridges. Holds the hashed fingerprint of the bridge’s
           identity key. (That is, the hash of the hash of the identity key.)

       DataDirectory/approved-routers
           Only used by authoritative directory servers. This file lists the
           status of routers by their identity fingerprint. Each line lists a
           status and a fingerprint separated by whitespace. See your
           fingerprint file in the DataDirectory for an example line. If the
           status is !reject then descriptors from the given identity
           (fingerprint) are rejected by this server. If it is !invalid then
           descriptors are accepted but marked in the directory as not valid,
           that is, not recommended.

       DataDirectory/v3-status-votes
           Only for v3 authoritative directory servers. This file contains
           status votes from all the authoritative directory servers.

       CacheDirectory/unverified-consensus
           This file contains a network consensus document that has been
           downloaded, but which we didn’t have the right certificates to
           check yet.

       CacheDirectory/unverified-microdesc-consensus
           This file contains a microdescriptor-flavored network consensus
           document that has been downloaded, but which we didn’t have the
           right certificates to check yet.

       DataDirectory/unparseable-desc
           Onion server descriptors that Tor was unable to parse are dumped to
           this file. Only used for debugging.

       DataDirectory/router-stability
           Only used by authoritative directory servers. Tracks measurements
           for router mean-time-between-failures so that authorities have a
           good idea of how to set their Stable flags.

       DataDirectory/stats/dirreq-stats
           Only used by directory caches and authorities. This file is used to
           collect directory request statistics.

       DataDirectory/stats/entry-stats
           Only used by servers. This file is used to collect incoming
           connection statistics by Tor entry nodes.

       DataDirectory/stats/bridge-stats
           Only used by servers. This file is used to collect incoming
           connection statistics by Tor bridges.

       DataDirectory/stats/exit-stats
           Only used by servers. This file is used to collect outgoing
           connection statistics by Tor exit routers.

       DataDirectory/stats/buffer-stats
           Only used by servers. This file is used to collect buffer usage
           history.

       DataDirectory/stats/conn-stats
           Only used by servers. This file is used to collect approximate
           connection history (number of active connections over time).

       DataDirectory/stats/hidserv-stats
           Only used by servers. This file is used to collect approximate
           counts of what fraction of the traffic is hidden service rendezvous
           traffic, and approximately how many hidden services the relay has
           seen.

       DataDirectory/networkstatus-bridges
           Only used by authoritative bridge directories. Contains information
           about bridges that have self-reported themselves to the bridge
           authority.

       DataDirectory/approved-routers
           Authorities only. This file is used to configure which relays are
           known to be valid, invalid, and so forth.

       HiddenServiceDirectory/hostname
           The <base32-encoded-fingerprint>.onion domain name for this hidden
           service. If the hidden service is restricted to authorized clients
           only, this file also contains authorization data for all clients.

           Note that clients will ignore any extra subdomains prepended to a
           hidden service hostname. So if you have "xyz.onion" as your
           hostname, you can tell clients to connect to "www.xyz.onion" or
           "irc.xyz.onion" for virtual-hosting purposes.

       HiddenServiceDirectory/private_key
           The private key for this hidden service.

       HiddenServiceDirectory/client_keys
           Authorization data for a hidden service that is only accessible by
           authorized clients.

       HiddenServiceDirectory/onion_service_non_anonymous
           This file is present if a hidden service key was created in
           HiddenServiceNonAnonymousMode.

SEE ALSO
       torsocks(1), torify(1)

       https://www.torproject.org/

       torspec: https://spec.torproject.org

BUGS
       Plenty, probably. Tor is still in development. Please report them at
       https://trac.torproject.org/.

AUTHORS
       Roger Dingledine [arma at mit.edu], Nick Mathewson [nickm at
       alum.mit.edu].



Tor                               02/21/2019                            TOR(1)