radvd.conf

RADVD.CONF(5)                                                    RADVD.CONF(5)



NAME
       radvd.conf - configuration file of the router advertisement daemon
       radvd

DESCRIPTION
       This file describes the information which is included in the router
       advertisement (RA) of a specific interface.

       The file contains one or more interface definitions of the form:

       interface name {
            list of interface specific options
            list of prefix definitions
            list of clients (IPv6 addresses) to advertise to
            list of route definitions
            list of RDNSS definitions
            list of DNSSL definitions
            list of ABRO definitions
            list of acceptable RA source addresses
       };

       All the possible interface specific options are detailed below.  Each
       option has to be terminated by a semicolon.

       Prefix definitions are of the form:

       prefix prefix/length {
            list of prefix specific options
       };

       Prefix can be network prefix or the address of the interface.  The
       address of interface should be used when using Mobile IPv6 extensions.

       Special prefix "::/64" is also supported on systems that implement
       getifaddrs() (on other systems, configuration activation fails and
       radvd exits).  When configured, radvd picks all non-link-local prefix
       assigned to the interface and starts advertising it.  This may be
       applicable in non-6to4 scenarios where the upstream prefix might
       change.  This option is incompatible with Base6to4Interface option.
       AdvRouterAddr option is always enabled when this configuration is used.

       All the possible prefix specific options are described below.  Each
       option has to be terminated by a semicolon.

       Decimal values are allowed only for MinDelayBetweenRAs,
       MaxRtrAdvInterval and MinRtrAdvInterval.  Decimal values should be used
       only when using Mobile IPv6 extensions.

       Route definitions are of the form:

       route prefix/length {
            list of route specific options
       };

       The prefix of a route definition should be network prefix; it can be
       used to advertise more specific routes to the hosts.

       RDNSS (Recursive DNS server) definitions are of the form:

       RDNSS ip [ip] [ip] {
            list of rdnss specific options
       };

       DNSSL (DNS Search List) definitions are of the form:

       DNSSL suffix [suffix] [suffix] [...] {
            list of dnssl specific options
       };

       By default radvd will send multicast route advertisements so that every
       node on the link can use them.  The list of clients (IPv6 address) to
       advertise to, and accept route solicitations from can be configured.
       If done, radvd does not send send messages to the multicast addresses
       but to the configured unicast addresses only.  Solicitations from other
       addresses are refused.  This is similar to UnicastOnly but includes
       periodic messages and incoming client access configuration.  See
       examples section for a use case of this.

       The definitions are of the form:

       clients {
               list of IPv6 addresses
       };

       By default radvd will use the first link-local address for the
       interface as the source address for route advertisements. This can be
       overwritten by manually setting the list of acceptable source
       addresses. If done, radvd will use the first address from the interface
       that is present in the configured source addresses only. This
       functionality will NOT spoof the source address, but may be useful in
       combination with VRRP or other functionality that

       AdvRASrcAddress {
               list of IPv6 addresses
       };

       ABRO (Authoritative Border Router Option) definitions are of the form:

       abro IPv6-address {
               list of abro specific options
       };


INTERFACE SPECIFIC OPTIONS
       IgnoreIfMissing on|off

              A flag indicating whether or not the interface is ignored if it
              does not exist at start-up.  By default, radvd exits.

              This is useful for dynamic interfaces which are not active when
              radvd starts or which are dynamically disabled and re-enabled
              during the time radvd runs.

              Current versions of radvd automatically try to re-enable
              interfaces.

              Enabling IgnoreIfMissing also quenches certain warnings in log
              messages relating to missing interfaces.

              Default: on


       AdvSendAdvert on|off

              A flag indicating whether or not the router sends periodic
              router advertisements and responds to router solicitations.

              This option no longer has to be specified first, but it needs to
              be on to enable advertisement on this interface.

              Default: off


       UnicastOnly on|off

              Indicates that the interface link type only supports unicast.
              This will prevent unsolicited advertisements from being sent,
              and will cause solicited advertisements to be unicast to the
              soliciting node.  This option is necessary for non-broadcast,
              multiple-access links, such as ISATAP.

              Default: off


       AdvRASolicitedUnicast on|off

              Indicates that router solicitations will be responded to with
              unicast router advertisements, as recommended by RFC7772. Large
              networks with a high concentration of mobile devices might
              experience like battery depletion, when solicited Router
              Advertisement messages are multicast.

              This corresponds to the Cisco IOS option ipv6 nd ra solicited
              unicast

              Default: on


       MaxRtrAdvInterval seconds

              The maximum time allowed between sending unsolicited multicast
              router advertisements from the interface, in seconds.

              Must be no less than 4 seconds and no greater than 1800 seconds.

              Minimum when using Mobile IPv6 extensions: 0.07.

              For values less than 0.2 seconds, 0.02 seconds is added to
              account for scheduling granularities as specified in RFC3775.

              Default: 600 seconds


       MinRtrAdvInterval seconds

              The minimum time allowed between sending unsolicited multicast
              router advertisements from the interface, in seconds.

              Must be no less than 3 seconds and no greater than 0.75 *
              MaxRtrAdvInterval.

              Minimum when using Mobile IPv6 extensions: 0.03.

              Default: 0.33 * MaxRtrAdvInterval


       MinDelayBetweenRAs seconds

              The minimum time allowed between sending multicast router
              advertisements from the interface, in seconds.

              This applies to solicited multicast RAs.  This is defined as the
              protocol constant MIN_DELAY_BETWEEN_RAS in RFC4861.  MIPv6
              redefines this parameter to have a minimum of 0.03 seconds.

              Minimum when using Mobile IPv6 extensions: 0.03.

              Default: 3


       AdvManagedFlag on|off

              When set, hosts use the administered (stateful) protocol for
              address autoconfiguration in addition to any addresses
              autoconfigured using stateless address autoconfiguration.  The
              use of this flag is described in RFC 4862.

              Default: off


       AdvOtherConfigFlag on|off

              When set, hosts use the administered (stateful) protocol for
              autoconfiguration of other (non-address) information.  The use
              of this flag is described in RFC 4862.

              Default: off


       AdvLinkMTU integer

              The MTU option is used in  router advertisement messages to
              insure that all nodes on a link use the same MTU value in those
              cases where the link MTU is not well known.

              If specified, i.e. not 0, must not be smaller than 1280 and not
              greater than the maximum MTU allowed for this link (e.g.
              ethernet has a maximum MTU of 1500. See RFC 4864).

              Default: 0


       AdvReachableTime milliseconds

              The time, in milliseconds, that a node assumes a neighbor is
              reachable after having received a reachability confirmation.
              Used by the Neighbor Unreachability Detection algorithm (see
              Section 7.3 of RFC 4861).  A value of zero means unspecified (by
              this router).

              Must be no greater than 3,600,000 milliseconds (1 hour).

              Default: 0


       AdvRetransTimer milliseconds

              The time, in milliseconds, between retransmitted Neighbor
              Solicitation messages.  Used by address resolution and the
              Neighbor Unreachability Detection algorithm (see Sections 7.2
              and 7.3 of RFC 4861).  A value of zero means unspecified (by
              this router).

              Default: 0


       AdvCurHopLimit integer

              The default value that should be placed in the Hop Count field
              of the IP header for outgoing (unicast) IP packets.  The value
              should be set to the current diameter of the Internet.  The
              value zero means unspecified (by this router).

              Default: 64


       AdvDefaultLifetime seconds

              The lifetime associated with the default router in units of
              seconds.  The maximum value corresponds to 18.2 hours.  A
              lifetime of 0 indicates that the router is not a default router
              and should not appear on the default router list.  The router
              lifetime applies only to the router's usefulness as a default
              router; it does not apply to information contained in other
              message fields or options.  Options that need time limits for
              their information include their own lifetime fields.

              Must be either zero or between MaxRtrAdvInterval and 9000
              seconds.

              Default: 3 * MaxRtrAdvInterval (Minimum 1 second).


       AdvDefaultPreference low|medium|high

              The preference associated with the default router, as either
              "low", "medium", or "high".

              Default: medium


       AdvSourceLLAddress on|off

              When set, the link-layer address of the outgoing interface is
              included in the RA.

              Default: on


       AdvHomeAgentFlag on|off

              When set, indicates that sending router is able to serve as
              Mobile IPv6 Home Agent.  When set, minimum limits specified by
              Mobile IPv6 are used for MinRtrAdvInterval and
              MaxRtrAdvInterval.

              Default: off


       AdvHomeAgentInfo on|off

              When set, Home Agent Information Option (specified by Mobile
              IPv6) is included in Router Advertisements.  AdvHomeAgentFlag
              must also be set when using this option.

              Default: off


       HomeAgentLifetime seconds

              The length of time in seconds (relative to the time the packet
              is sent) that the router is offering Mobile IPv6 Home Agent
              services.  A value 0 must not be used.  The maximum lifetime is
              65520 seconds (18.2 hours).  This option is ignored, if
              AdvHomeAgentInfo is not set.

              If both HomeAgentLifetime and HomeAgentPreference are set to
              their default values, Home Agent Information Option will not be
              sent.

              Default: AdvDefaultLifetime


       HomeAgentPreference integer

              The preference for the Home Agent sending this Router
              Advertisement.  Values greater than 0 indicate more preferable
              Home Agent, values less than 0 indicate less preferable Home
              Agent.  This option is ignored, if AdvHomeAgentInfo is not set.

              If both HomeAgentLifetime and HomeAgentPreference are set to
              their default values, Home Agent Information Option will not be
              sent.

              Default: 0


       AdvMobRtrSupportFlag on|off

              When set, the Home Agent signals it supports Mobile Router
              registrations (specified by NEMO Basic).  AdvHomeAgentInfo must
              also be set when using this option.

              Default: off


       AdvIntervalOpt on|off

              When set, Advertisement Interval Option (specified by Mobile
              IPv6) is included in Router Advertisements.  When set, minimum
              limits specified by Mobile IPv6 are used for MinRtrAdvInterval
              and MaxRtrAdvInterval.

              The advertisement interval is based on the configured
              MaxRtrAdvInterval parameter except where this is less than
              200ms.  In this case, the advertised interval is (
              MaxRtrAdvInterval + 20ms ).

              Default: off


PREFIX SPECIFIC OPTIONS
       AdvOnLink on|off

              When set, indicates that this prefix can be used for on-link
              determination.  When not set the advertisement makes no
              statement about on-link or off-link properties of the prefix.
              For instance, the prefix might be used for address configuration
              with some of the addresses belonging to the prefix being on-link
              and others being off-link.

              Default: on


       AdvAutonomous on|off

              When set, indicates that this prefix can be used for autonomous
              address configuration as specified in RFC 4862.

              Default: on


       AdvRouterAddr on|off

              When set, indicates that the address of interface is sent
              instead of network prefix, as is required by Mobile IPv6.  When
              set, minimum limits specified by Mobile IPv6 are used for
              MinRtrAdvInterval and MaxRtrAdvInterval.

              Default: off


       AdvValidLifetime seconds|infinity

              The length of time in seconds (relative to the time the packet
              is sent) that the prefix is valid for the purpose of on-link
              determination.  The symbolic value infinity represents infinity
              (i.e. a value of all one bits (0xffffffff)).  The valid lifetime
              is also used by RFC 4862.

              Note that clients will ignore AdvValidLifetime of an existing
              prefix if the lifetime is below two hours, as required in RFC
              4862 Section 5.5.3 point e).

              Note: RFC4861's suggested default value is significantly longer:
              30 days.

              Default: 86400 seconds (1 day)


       AdvPreferredLifetime seconds|infinity

              The length of time in seconds (relative to the time the packet
              is sent) that addresses generated from the prefix via stateless
              address autoconfiguration remain preferred.  The symbolic value
              infinity represents infinity (i.e. a value of all one bits
              (0xffffffff)).  See RFC 4862.

              Note: RFC4861's suggested default value is significantly longer:
              7 days.

              Default: 14400 seconds (4 hours)


       DeprecatePrefix on|off

              Upon shutdown, this option will cause radvd to deprecate the
              prefix by announcing it in the radvd shutdown RA with a zero
              preferred lifetime and a valid lifetime slightly greater than 2
              hours. This will encourage end-nodes using this prefix to
              deprecate any associated addresses immediately. Note that this
              option should only be used when only one router is announcing
              the prefix onto the link, otherwise end-nodes will deprecate
              associated addresses despite the prefix still being valid for
              preferred use.

              See RFC4862, section 5.5.3., "Router Advertisement Processing",
              part (e).

              Default: off


       DecrementLifetimes on|off

              This option causes radvd to decrement the values of the
              preferred and valid lifetimes for the prefix over time. The
              lifetimes are decremented by the number of seconds since the
              last RA. If radvd receives a SIGUSR1 signal, it will reset the
              values of the preferred and valid lifetimes back to the initial
              values used by radvd when it started. If radvd never receives a
              SIGUSR1 signal, it will continue to decrement the lifetimes
              until the preferred lifetime reaches zero. After a final RA with
              a zero value preferred lifetime, radvd will cease to announce
              the prefix. If a SIGUSR1 signal then causes the lifetimes to be
              reset, the prefix will then re-appear in the RAs.

              This option is intended to be used in conjunction with a DHCPv6
              client that is using the Identity Association for Prefix
              Delegation (IA_PD) option to acquire a prefix from a Delegating
              Router for use by a Requesting Router. In this scenario, the
              prefix(es) from within the delegated prefix that are announced
              by radvd would age in parallel with and at the same rate as the
              delegated prefix, and expire at approximately the same time, if
              the delegated prefix's life isn't extended.

              See RFC3633, "IPv6 Prefix Options for Dynamic Host Configuration
              Protocol (DHCP) version 6".

              Default: off


       Base6Interface name

              If this options is specified, this prefix will be combined with
              the IPv6 address of the interface specified by name.  The
              resulting prefix length will be 64.


       Base6to4Interface name

              If this option is specified, this prefix will be combined with
              the IPv4 address of interface name to produce a valid 6to4
              prefix. The first 16 bits of this prefix will be replaced by
              2002 and the next 32 bits of this prefix will be replaced by the
              IPv4 address assigned to interface name at configuration time.
              The remaining 80 bits of the prefix (including the SLA ID) will
              be advertised as specified in the configuration file.  See the
              next section for an example.

              If interface name is not available at configuration time, a
              warning will be written to the log and this prefix will be
              disabled until radvd is reconfigured.

              This option enables systems with dynamic IPv4 addresses to
              update their advertised 6to4 prefixes simply by restarting radvd
              or sending a SIGHUP signal to cause radvd to reconfigure itself.

              Note that 6to4 prefixes derived from dynamically-assigned IPv4
              addresses should be advertised with a significantly shorter
              lifetime (see the AdvValidLifetime and AdvPreferredLifetime
              options).

              For more information on 6to4, see RFC 3056.

              Default: 6to4 is not used


ROUTE SPECIFIC OPTIONS
       AdvRouteLifetime seconds|infinity

              The lifetime associated with the route in units of seconds.  The
              symbolic value infinity represents infinity (i.e. a value of all
              one bits (0xffffffff)).

              Default: 3 * MaxRtrAdvInterval


       AdvRoutePreference low|medium|high

              The preference associated with the default router, as either
              "low", "medium", or "high".

              Default: medium


       RemoveRoute on|off

              Upon shutdown, announce this route with a zero second lifetime.
              This should cause the route to be immediately removed from the
              receiving end-nodes' route table.

              Default: on


RDNSS SPECIFIC OPTIONS
       AdvRDNSSLifetime seconds|infinity
              The maximum duration how long the RDNSS entries are used for
              name resolution. A value of 0 means the nameserver must no
              longer be used. The value, if not 0, must be at least
              MaxRtrAdvInterval.  To ensure stale RDNSS info gets removed in a
              timely fashion, this should not be greater than
              2*MaxRtrAdvInterval.

              Default: 2*MaxRtrAdvInterval


       FlushRDNSS on|off

              Upon shutdown, announce the RDNSS entries with a zero second
              lifetime. This should cause the RDNSS addresses to be
              immediately removed from the end-nodes' list of Recursive DNS
              Servers.

              Default: on


DNSSL SPECIFIC OPTIONS
       AdvDNSSLLifetime seconds|infinity;
              The maximum duration how long the DNSSL entries are used for
              name resolution.  A value of 0 means the suffix should no longer
              be used.  The value, if not 0, must be at least
              MaxRtrAdvInterval.  To ensure stale DNSSL info gets removed in a
              timely fashion, this should not be greater than
              2*MaxRtrAdvInterval.

              Default: 2*MaxRtrAdvInterval


       FlushDNSSL on|off

              Upon shutdown, announce the DNSSL entries with a zero second
              lifetime. This should cause the DNSSL entries to be immediately
              removed from the end-nodes' DNS search list.

              Default: on


ABRO SPECIFIC OPTIONS
       AdvValidLifeTime seconds
              The time in units of that the set of border router information
              is valid.  A value of all zero bits assumes a default value of
              10,000(~one week).


       AdvVersionLow, AdvVersionHigh unsignedinteger
              Both forms 32-bit unsigned version number corresponding to the
              set of information contained in RA message.


EXAMPLES
       interface eth0
       {
               AdvSendAdvert on;
               prefix 2001:db8:0:1::/64
               {
                       AdvOnLink on;
                       AdvAutonomous on;
               };
       };

       It says that router advertisement daemon should advertise
       (AdvSendAdvert on;) the prefix 2001:db8:0:1:: which has a length of 64
       on the interface eth0.  Also the prefix should be marked as autonomous
       (AdvAutonomous on;) and as on-link (AdvOnLink on;).  All the other
       options are left on their default values.

       To support movement detection of Mobile IPv6 Mobile Nodes, the address
       of interface should be used instead of network prefix:

       interface eth0
       {
               AdvSendAdvert on;
               prefix 2001:db8:0:1::4/64
               {
                       AdvOnLink on;
                       AdvAutonomous on;
                       AdvRouterAddr on;
               };
       };

       For 6to4 support, include the Base6to4Interface option in each prefix
       section. When using a dynamic IPv4 address, set small prefix lifetimes
       to prevent hosts from retaining unreachable prefixes after a new IPv4
       address has been assigned.  When advertising to on a dynamic interface
       (e.g., Bluetooth), skip the interface if it is not active yet.

       interface bnep0
       {
               IgnoreIfMissing on;
               AdvSendAdvert on;

               # Advertise at least every 30 seconds
               MaxRtrAdvInterval 30;

               prefix 0:0:0:5678::/64
               {
                       AdvOnLink on;
                       AdvAutonomous on;
                       Base6to4Interface ppp0;

                       # Very short lifetimes for dynamic addresses
                       AdvValidLifetime 300;
                       AdvPreferredLifetime 120;
               };
       };

       Since 6to4 is enabled, the prefix will be advertised as
       2002:WWXX:YYZZ:5678::/64, where WW.XX.YY.ZZ is the IPv4 address of ppp0
       at configuration time. (IPv6 addresses are written in hexadecimal
       whereas IPv4 addresses are written in decimal, so the IPv4 address
       WW.XX.YY.ZZ in the 6to4 prefix will be represented in hex.)

       In this specific case, the configuration scripts may send HUP signal to
       radvd when taking bnep0 up or down to notify about the status; in the
       current radvd releases, sending HUP is no longer mandatory when the
       link comes back up.

       interface eth0
       {
               AdvSendAdvert on;
               prefix 2001:db8:0:1::/64
               {
                       AdvOnLink on;
                       AdvAutonomous on;
               };
               clients
               {
                       fe80::21f:16ff:fe06:3aab;
                       fe80::21d:72ff:fe96:aaff;
               };
       };

       This configuration would only announce the prefix to
       fe80::21f:16ff:fe06:3aab and fe80::21d:72ff:fe96:aaff.  Furthermore,
       all RA requests of other clients are denied.

       This may come in handy if you want to roll out IPv6 only partially
       because some clients are broken or untested.

       For ABRO support
       interface lowpan0
       {
            AdvSendAdvert on;
            UnicastOnly on;
            AdvCurHopLimit 255;
            prefix 2001:0db8:0100:f101::/64 {
                 AdvOnLink on;
                 AdvAutonomous on;
                 AdvRouterAddr on;
            };
            abro fe80::a200:0:0:1/64 {
                 AdvVersionLow 10;
                 AdvVersionHigh 2;
                 AdvValidLifeTime 2;
            };
       };


FILES
       /usr/sbin/radvd
       /etc/radvd.conf
       /var/run/radvd.pid
       /var/log/radvd.log


CREDIT
       The description of the different flags and variables is in large parts
       taken from RFC 4861.


RFCS
       Narten, T., Nordmark, E., Simpson, W., and H. Soliman, "Neighbor
       Discovery for IP Version 6 (IPv6)", RFC 4861, September 2007.

       Thomson, S., Narten, T., T. Jinmei, "IPv6 Stateless Address
       Autoconfiguration", RFC 4862, September 2007.

       Deering, S., and R. Hinden, "IP Version 6 Addressing Architecture", RFC
       4291, February 2006.

       Conta, A., Deering, S., and M. Gupta "Internet Control Message Protocol
       (ICMPv6) for the Internet Protocol Version 6 (IPv6)", RFC 4443, March
       2006.

       Crawford, M., "Transmission of IPv6 Packets over Ethernet Networks",
       RFC 2464, December 1998.

       Carpenter B., K. Moore, "Connection of IPv6 Domains via IPv4 Clouds",
       RFC 3056, February 2001. (6to4 specification)

       Draves, R., D. Thaler, "Default Router Preferences and More-Specific
       Routes", RFC 4191, November 2005.

       Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in IPv6", RFC
       3775, June 2004.

       Devarapalli, V., Wakikawa, R., Petrescu, A., and P. Thubert "Network
       Mobility (NEMO) Basic Support Protocol", RFC 3963, January 2005.

       J. Jeong, S. Park, L. Beloeil, and S. Madanapalli, "IPv6 Router
       Advertisement Options for DNS Configuration", RFC 6106, November 2010.

       Z. Shelby, S. Chakrabarti, E. Nordmark and  C. Bormann " Neighbor
       Discovery Optimization for IPv6 over Low-Power Wireless Personal Area
       Networks (6LoWPANs)", RFC 6775, November 2012.

       Gont, F. "Security Implications of IPv6 Fragmentation with IPv6
       Neighbor Discovery", RFC 6980, August 2013.

       Yourtchenko, A. and Colitti, L. "Reducing Energy Consumption of Router
       Advertisements", RFC 7772, February 2016.


SEE ALSO
       radvd(8), radvdump(8)



radvd 2.17                        4 Jan 2011                     RADVD.CONF(5)