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.\"     $Id: rtadvd.8,v 1.1.1.1 1999/08/08 23:31:42 itojun Exp $
.\"     $FreeBSD$
.\"
.Dd May 17, 1998
.Dt RTADVD 8
.Os KAME
.Sh NAME
.Nm rtadvd
.Nd router advertisement daemon
.Sh SYNOPSIS
.Nm
.Op Fl c Ar configfile
.Op Fl P Ar policy
.Op Fl dDfs
.Ar interface ...
.Sh DESCRIPTION
.Nm Rtadvd
advertises router advertisement packet to the specified
.Ar interfaces .
.Pp
The program will daemonize itself on invocation.
Then, it will voluntarily send router advertisement packet periodically.
If a router solicitation packet from host has reached the program,
the program will respond by router advertisement packet.
.Pp
For each interface, which is called advertising interface,
content of router advertisement can be described in
.Xr rtadvd.conf 5 .
.Pp
If there is no description for the interface in the configuration file
or if the configuration file does not exist,
.Nm
sets all the parameters to their default values.
In particular,
.Nm
gets all the interface routes from the routing table and advertises
them as on-link prefixes.
.Pp
.Nm Rtadvd
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.
If you do not want to enable this feature, you should specify the
.Ic Fl s
command line option when advocation.
.Pp
.Nm Rtadvd
can also receive router renumbering packets, and can do router
renumbering for the system it runs on, as the contents of those
packets.
.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 P
Specifies that
.Nm
receives router renumbering messages.
Also, specifies IPsec policy for
rrenumd sessions.
Because router renumbering can change the system's
IPv6 prefix, its messages must be protected by IPsec.
For details about
.Ar policy ,
please refer to
.Xr ipsec 4
and
.Xr ipsec_set_policy 3 .
.It Fl d
Debug.
.It Fl D
More debug.
.It Fl f
Foreground mode.
Do not become daemon.
.It Fl s
Static prefix.
Do not watch the routing table.
.El
.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
Do not perform router advertisement toward upstream direction,
you should only advertise to downstream direction.
If you advertise toward upstream by mistake,
you will see icmp6 redirect storm on that subnet.
This is because of the specification,
which says that advertising router is assumed to become
the default outgoing router for end hosts in the subnet.