Command Section
RTADVD(8)               FreeBSD System Manager's Manual              RTADVD(8)

     rtadvd - router advertisement daemon

     rtadvd [-dDfRs] [-c configfile] [-C ctlsock] [-M ifname] [-p pidfile]
            [interface ...]

     rtadvd sends router advertisement packets to the specified interfaces.
     If no interfaces are specified, rtadvd will still run, but will not
     advertise any routes until interfaces are added using rtadvctl(8).

     The program will daemonize itself on invocation.  It will then send
     router advertisement packets periodically, as well as in response to
     router solicitation messages sent by end hosts.

     Router advertisements can be configured on a per-interface basis, as
     described in rtadvd.conf(5).

     If there is no configuration file entry for an interface, or if the
     configuration file does not exist altogether, rtadvd sets all the
     parameters to their default values.  In particular, rtadvd reads all the
     interface routes from the routing table and advertises them as on-link

     rtadvd also watches the routing table.  If an interface direct route is
     added on an advertising interface and no static prefixes are specified by
     the configuration file, rtadvd adds the corresponding prefix to its
     advertising list.

     Similarly, when an interface direct route is deleted, rtadvd will start
     advertising the prefixes with zero valid and preferred lifetimes to help
     the receiving hosts switch to a new prefix when renumbering.  Note,
     however, that the zero valid lifetime cannot invalidate the
     autoconfigured addresses at a receiving host immediately.  According to
     the specification, the host will retain the address for a certain period,
     which will typically be two hours.  The zero lifetimes rather intend to
     make the address deprecated, indicating that a new non-deprecated address
     should be used as the source address of a new connection.  This behavior
     will last for two hours.  Then rtadvd will completely remove the prefix
     from the advertising list, and succeeding advertisements will not contain
     the prefix information.

     Moreover, if the status of an advertising interface changes, rtadvd will
     start or stop sending router advertisements according to the latest

     The -s option may be used to disable this behavior; rtadvd will not watch
     the routing table and the whole functionality described above will be

     Basically, hosts MUST NOT send Router Advertisement messages at any time
     (RFC 4861, Section 6.2.3).  However, it would sometimes be useful to
     allow hosts to advertise some parameters such as prefix information and
     link MTU.  Thus, rtadvd can be invoked if router lifetime is explicitly
     set zero on every advertising interface.

     The command line options are:

     -c      Specify an alternate location, configfile, for the configuration
             file.  By default, /etc/rtadvd.conf is used.

     -C      Specify an alternate location for the control socket used by
             rtadvctl(8).  The default is /var/run/rtadvd.sock.

     -d      Print debugging information.

     -D      Even more debugging information is printed.

     -f      Foreground mode (useful when debugging).  Log messages will be
             dumped to stderr when this option is specified.

     -M      Specify an interface to join the all-routers site-local multicast
             group.  By default, rtadvd tries to join the first advertising
             interface appearing on the command line.  This option has meaning
             only with the -R option, which enables routing renumbering
             protocol support.

     -p      Specify an alternative file in which to store the process ID.
             The default is /var/run/

     -R      Accept router renumbering requests.  If you enable it, certain
             IPsec setup is suggested for security reasons.  This option is
             currently disabled, and is ignored by rtadvd with a warning

     -s      Do not add or delete prefixes dynamically.  Only statically
             configured prefixes, if any, will be advertised.

     Use SIGHUP to reload the configuration file /etc/rtadvd.conf.  If an
     invalid parameter is found in the configuration file upon the reload, the
     entry will be ignored and the old configuration will be used.  When
     parameters in an existing entry are updated, rtadvd will send Router
     Advertisement messages with the old configuration but zero router
     lifetime to the interface first, and then start to send a new message.

     Use SIGTERM to kill rtadvd gracefully.  In this case, rtadvd will
     transmit router advertisement with router lifetime 0 to all the
     interfaces (in accordance with RFC 4861 6.2.5).

     /etc/rtadvd.conf                  The default configuration file.
     /var/run/               The default process ID file.

     The rtadvd utility exits 0 on success, and >0 if an error occurs.

     rtadvd.conf(5), rtadvctl(8), rtsol(8)

     Thomas Narten, Erik Nordmark, W. A. Simpson, and Hesham Soliman, Neighbor
     Discovery for IP version 6 (IPv6), RFC 4861.

     Thomas Narten, Erik Nordmark, and W. A. Simpson, Neighbor Discovery for
     IP version 6 (IPv6), RFC 2461 (obsoleted by RFC 4861).

     Richard Draves, Default Router Preferences and More-Specific Routes,

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

     The rtadvd command first appeared in the WIDE Hydrangea IPv6 protocol
     stack kit.

     There used to be some text that recommended users not to let rtadvd
     advertise Router Advertisement messages on an upstream link to avoid
     undesirable icmp6(4) redirect messages.  However, based on the later
     discussion in the IETF ipng working group, all routers should rather
     advertise the messages regardless of the network topology, in order to
     ensure reachability.

FreeBSD 11.1-RELEASE-p4        February 25, 2013       FreeBSD 11.1-RELEASE-p4
Command Section