.\"	$OpenBSD: rtadvd.8,v 1.7 2000/02/02 04:10:37 itojun Exp $
.\" 
.\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
.\" All rights reserved.
.\" 
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the project nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\" 
.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     KAME Id: rtadvd.8,v 1.4 2000/02/02 03:55:44 itojun Exp
.\"
.Dd May 17, 1998
.Dt RTADVD 8
.Os
.Sh NAME
.Nm rtadvd
.Nd router advertisement daemon
.Sh SYNOPSIS
.Nm
.Op Fl c Ar configfile
.Op Fl dDfsR
.Ar interface ...
.Sh DESCRIPTION
.Nm Rtadvd
advertises router advertisement packet to the specified
.Ar interfaces .
.Pp
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.
.Pp
Router advertisements can be configured on a per-interface basis, as
described in
.Xr rtadvd.conf 5 .
.Pp
In the event of no configuration file entry for an interface,
or if the configuration file does not exist altogether,
.Nm
sets all the parameters to their default values.
In particular,
.Nm
reads all the interface routes from the routing table and advertises
them as on-link prefixes.
.Pp
.Nm Rtadvd
also watches the routing table.
By default, if an interface direct route is
added/deleted on an advertising interface,
.Nm
adds/deletes the corresponding prefix to/from its advertising list,
respectively.
The
.Ic Fl s
command line option may be used to disable this behavior.
.Pp
The command line options are:
.Bl -tag -width indent
.\"
.It Fl c
Specify an alternate location,
.Ar configfile ,
for the configuration file.
By default,
.Pa /etc/rtadvd.conf
is used.
.It Fl d
Print debugging information.
.It Fl D
Even more debugging information is printed.
.It Fl f
Foreground mode (useful when debugging).
.It Fl s
Do not monitor routing table changes (static prefix).
.It Fl R
Accept router renumbering requests.
If you enable it, certain IPsec setup is suggested for security reasons.
.El
.Pp
Use
.Dv SIGTERM
to kill
.Nm
gracefully.
In this case,
.Nm
will transmit router advertisement with router lifetime 0
to all the interfaces
.Pq according to RFC2461 6.2.5 .
.Sh RETURN VALUES
The program exits with 0 on success, and non-zero on failures.
.Sh FILES
.Bl -tag -width /etc/rtadvd.conf -compact
.It Pa /etc/rtadvd.conf
The default configuration file.
.El
.Sh SEE ALSO
.Xr daemon 3 ,
.Xr rtadvd.conf 5 ,
.Xr rtsol 8
.Sh HISTORY
The
.Nm
command first appeared in WIDE Hydrangea IPv6 protocol stack kit.
.Sh CAVEAT
Router advertisements should only be performed downstream.
Erroneous upstream advertisements will cause
.Xr icmp6 4
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.