DESCRIPTION

     rtadvd sends router advertisement packets to the specified interfaces.

     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 con-
     figuration 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 prefixes.

     rtadvd also watches the routing table.  By default, if an interface
     direct route is added/deleted on an advertising interface and no static
     prefixes are specified by the configuration file, rtadvd adds/deletes the
     corresponding prefix to/from its advertising list, respectively.  The -s
     option may be used to disable this behavior.  Moreover, if the status of
     an advertising interface changes, rtadvd will start or stop sending
     router advertisements according to the latest status.

     Basically, hosts MUST NOT send Router Advertisement messages at any time
     (RFC 2461, 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.

     -d      Print debugging information.

     -D      Even more debugging information is printed.

     -f      Foreground mode (useful when debugging).

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

     -R      Accept router renumbering requests.  If you enable it, certain
             IPsec setup is suggested for security reasons.  On KAME-based
             systems, rrenumd(8) generates router renumbering request packets.
             This option is currently disabled, and is ignored by rtadvd with
             a warning message.

FILES

     /etc/rtadvd.conf                  The default configuration file.
     /var/run/rtadvd.pid               contains the pid of the currently run-
                                       ning rtadvd.
     /var/run/rtadvd.dump              in which rtadvd dumps its internal
                                       state.

SEE ALSO

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

HISTORY

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

CAVEAT

     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 dis-
     cussion in the IETF ipng working group, all routers should rather adver-
     tise the messages regardless of the network topology, in order to ensure
     reachability.

BSD                              May 17, 1998                              BSD