rtadvd - router advertisement daemon
rtadvd [-dDfMRs] [-c configfile] interface ...
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 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
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). Log messages will be
dumped to stderr when this option is specified.
-M Specify an interface to join the all-routers sitelocal 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.
-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 message.
-s Do not add or delete prefixes dynamically. Only
statically configured
prefixes, if any, will be advertised.
Upon receipt of signal SIGUSR1, rtadvd will dump the current
internal
state into /var/run/rtadvd.dump.
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 2461 6.2.5).
The rtadvd program exits 0 on success, and >0 on failures.
/etc/rtadvd.conf The default configuration
file.
/var/run/rtadvd.pid contains the pid of the
currently running
rtadvd.
/var/run/rtadvd.dump The file in which rtadvd
dumps its internal
state.
rtadvd.conf(5), rtsol(8)
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.
OpenBSD 3.6 May 17, 1998
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