2PING(1p)             User Contributed Perl Documentation            2PING(1p)

       2ping - A bi-directional ping client/listener

       2ping [ options ] --listen | host/IP

       2ping is a bi-directional ping utility.  It uses 3-way pings (akin to
       TCP SYN, SYN/ACK, ACK) and after-the-fact state comparison between a
       2ping listener and a 2ping client to determine which direction packet
       loss occurs.

       To use 2ping, start a listener on a known stable network host.  The
       relative network stability of the 2ping listener host should not be in
       question, because while 2ping can determine whether packet loss is
       occurring inbound or outbound relative to an endpoint, that will not
       help you determine the cause if both of the endpoints are in question.

       Once the listener is started, start 2ping in client mode and tell it to
       connect to the listener.  The ends will begin pinging each other and
       displaying network statistics.  If packet loss occurs, 2ping will wait
       a few seconds (default 10, configurable with -w) before comparing notes
       between the two endpoints to determine which direction the packet loss
       is occurring.

       To quit 2ping on the client or listener ends, enter ^C, and a list of
       statistics will be displayed.  To get a short inline display of
       statistics without quitting, send the process a QUIT signal (yes,
       that's the opposite of what you would think, but it's in line with the
       normal ping utility).

       ping-compatible options:

       -a  Audible ping.

       -A  Adaptive ping.  A new client ping request is sent as soon as a
           client ping response is received.  If a ping response is not
           received within the interval period, a new ping request is sent.
           Minimal interval is 200msec for not super-user.  On networks with
           low rtt this mode is essentially equivalent to flood mode.

           2ping-specific notes: This behavior is somewhat different to the
           nature of ping's adaptive ping, but the result is roughly the same.

       -c count
           Stop after sending count ping requests.

           2ping-specific notes: This option behaves slightly differently from
           ping.  If both -c and -w are specified, satisfaction of -c will
           cause an exit first.  Also, internally, 2ping exits just before
           sending count+1 pings, to give time for the ping to complete.

       -f  Flood ping. For every ping sent a period "." is printed, while for
           ever ping received a backspace is printed. This provides a rapid
           display of how many pings are being dropped.  If interval is not
           given, it sets interval to zero and outputs pings as fast as they
           come back or one hundred times per second, whichever is more.  Only
           the super-user may use this option with zero interval.

           2ping-specific notes: Detected outbound/inbound loss responses are
           printed as ">" and "<", respectively.  Receive errors are printed
           as "E".  Due to the asynchronous nature of 2ping, successful
           responses (backspaces) may overwrite these loss and error

       -i interval
           Wait interval seconds between sending each ping.  The default is to
           wait for one second between each ping normally, or not to wait in
           flood mode.  Only super-user may set interval to values less 0.2

       -I interface IP
           Set source IP address.  When pinging IPv6 link-local address this
           option is required.  When in listener mode, this option may be
           specified multiple to bind to multiple IP addresses.  When in
           client mode, this option may only be specified once, and all
           outbound pings will be bound to this source IP.

           2ping-specific notes: This option only takes an IP address, not a
           device name.  Note that in listener mode, if the machine has an
           interface with multiple IP addresses and an request comes in via a
           sub IP, the reply still leaves via the interface's main IP.  So
           this option must be used if you would like to respond via an
           interface's sub-IP.

       -l preload
           If preload is specified, 2ping sends that many packets not waiting
           for reply.  Only the super-user may select preload more than 3.

       -p pattern
           You may specify up to 16 "pad" bytes to fill out the packets you
           send.  This is useful for diagnosing data-dependent problems in a
           network.  For example, -p ff will cause the sent packet pad area to
           be filled with all ones.

           2ping-specific notes: This pads the portion of the packet that does
           not contain the active payload data.  If the active payload data is
           larger than the minimum packet size (--min-packet-size=min), no
           padding will be sent.

       -q  Quiet output.  Nothing is displayed except the summary lines at
           startup time and when finished.

       -s packetsize
           ping compatibility, this will set --min-packet-size to this plus 8

       -v  Verbose output.  In 2ping, this prints decodes of packets that are
           sent and received.

       -V  Show version and exit.

       -w deadline
           Specify a timeout, in seconds, before 2ping exits regardless of how
           many pings have been sent or received.  Due to blocking, this may
           occur up to one second after the deadline specified.

           2ping-specific notes: This option behaves slightly differently from
           ping.  If both -c and -w are specified, satisfaction of -c will
           cause an exit first.

       2ping-specific options:

       -?, --help
           Print a synposis and exit.

       -6, --ipv6
           Bind/connect as IPv6.

           Set a shared key, send cryptographic hashes with each packet, and
           require cryptographic hashes from peer packets signed with the same
           shared key.

           When --auth is used, specify the digest type to compute the
           cryptographic hash.  Valid options are hmac-md5 (default),
           hmac-sha1 and hmac-sha256.  hmac-md5 requires Digest::MD5, and the
           SHA digests require Digest::SHA.

           Print (lots of) debugging information.

           Wait at least secs seconds before inquiring about a lost packet.
           Default is 10 seconds.  UDP packets can arrive delayed or out of
           order, so it is best to give it some time before inquiring about a
           lost packet.

           Start as a listener.  The listener will not send out ping requests
           at regular intervals, and will instead wait for the far end to
           initiate ping requests.  A listener is required as the remote end
           for a client.

           Set the minimum total payload size to min bytes, default 128.  If
           the payload is smaller than min bytes, padding will be added to the
           end of the packet.

           Set the maximum total payload size to max bytes, default 512,
           absolute minimum 64.  If the payload is larger than max bytes,
           information will be rearranged and sent in future packets when

           Do not perform 3-way pings.  Used most often when combined with
           --listen, as the listener is usually the one to determine whether a
           ping reply should become a 3-way ping.

           Strictly speaking, a 3-way ping is not necessary for determining
           directional packet loss between the client and the listener.
           However, the extra leg of the 3-way ping allows for extra chances
           to determine packet loss more efficiently.  Also, with 3-way ping
           disabled, the listener will receive no client performance
           indicators, nor will the listener be able to determine directional
           packet loss that it detects.

           When sending replies, 2ping will try to match the packet size of
           the received packet by adding padding if necessary, but will not
           exceed --max-packet-size.  --no-match-packet-size disabled this
           behavior, always setting the minimum to --min-packet-size.

           Do not send the current running version of 2ping with each packet.

           Arbitrary notice text to send with each packet.  If the remote peer
           supports it, this may be displayed to the user.

           Simulate random packet loss outbound and inbound.  For example,
           25:10 means a 25% chance of not sending a packet, and a 10% chance
           of ignoring a received packet.  A single number without colon
           separation means use the same percentage for both outbound and

           Use UDP port port.  With --listen, this is the port to bind as,
           otherwise this is the port to send to.  Default is UDP port 15998.

           Print a line of brief current statistics every interval seconds.
           The same line can be printed on demand by sending SIGQUIT to the
           2ping process.

       There are probably lots and lots and lots of unknown bugs.

       By default, source IP logic doesn't work as expected, see -I for
       details.  There appears to be no way to peg the source IP of reply UDP
       packets to the destination of the packet that is being replied to.  As
       a result, packets always go out the interface's main IP address if not
       specified manually.  (Please, prove the author wrong.)

       This manpage isn't finished yet, and may never be.

       2ping was written by Ryan Finnie <ryan@finnie.org>.

perl v5.18.2                      2014-04-26                         2PING(1p)