`rtadvd`

Router advertisement daemon

Syntax:

rtadvd [-c configfile] [-dDfRs] interface ...

Options:

-c configfile: Specify an alternate location, configfile, for the configuration file. By default, /etc/rtadvd.conf is used.
-D: Log more verbose debugging information (than the -d option) to syslogd.
-d: Log verbose debugging information to syslogd.
-f: Prevent rtadvd from becoming a daemon (run in foreground mode); this is useful when debugging.
-R: Accept router renumbering requests. If you enable it, certain IPsec setup is suggested for security reasons.
-s: Do not add or delete prefixes dynamically. Only statically configured prefixes, if any, will be advertised.
interface: The interface name(s) to use when sending router advertisement packets.

Description:

The rtadvd daemon advertises router advertisement packet to the specified interfaces.

The program will daemonize itself on invocation. It will then periodically send router advertisement packets, 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.

If there is no configuration file or the interface doesn't have a configuration file entry, 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.

The daemon also watches the routing table. By default, 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, if such a route is deleted, rtadvd deletes the corresponding prefix from the list. The -s option disables this behavior. Moreover, if the status of an advertising interface changes, rtadvd will start or stop sending router advertisements according to the latest status.

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 (according to RFC2461 6.2.5).

Examples:

Start the router advertisement daemon:

rtadvd

Run the router advertisement program as a foreground process:

rtadvd -f

Files:

/etc/rtadvd.conf: default configuration file.
/var/run/rtadvd.pid: contains the PID of the currently running rtadvd.
/var/run/rtadvd.dump: the file on which rtadvd dumps its internal state.

Exit status:

0: Success.
> 0: An error occurred.

Author:

Authorship information is included in the copyright notice, see rtadvd in the appendix Third-Party Copyright Notices.

License:

This utility is based on copyright software; for the copyright notice, see rtadvd in the appendix Third-Party Copyright Notices.

Caveats:

Router advertisements should only be performed downstream. Erroneous upstream advertisements will cause ICMPv6 redirect packet storms in the subnet, as (per the specification) the advertising router is assumed to become the default router for end hosts in the subnet.