was removed from the kernel; Advertise the prefix with zero lifetimes rather than to remove the prefix from the prefix list to be advertised. This will help renumber a receiving host by deprecating the address derived from the old prefix. Obtained from: KAME MFC after: 2 weeks
202 lines
6.3 KiB
Groff
202 lines
6.3 KiB
Groff
.\" $FreeBSD$
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.\" $KAME: rtadvd.8,v 1.17 2001/02/04 05:34:38 jinmei Exp $
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.\"
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.\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the project nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.Dd May 17, 1998
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.Dt RTADVD 8
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.Os
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.Sh NAME
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.Nm rtadvd
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.Nd router advertisement daemon
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.Sh SYNOPSIS
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.Nm
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.Op Fl dDfMRs
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.Op Fl c Ar configfile
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.Ar interface ...
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.Sh DESCRIPTION
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.Nm
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sends router advertisement packets to the specified
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.Ar interfaces .
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.Pp
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The program will daemonize itself on invocation.
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It will then send router advertisement packets periodically, as well
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as in response to router solicitation messages sent by end hosts.
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.Pp
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Router advertisements can be configured on a per-interface basis, as
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described in
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.Xr rtadvd.conf 5 .
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.Pp
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If there is no configuration file entry for an interface,
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or if the configuration file does not exist altogether,
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.Nm
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sets all the parameters to their default values.
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In particular,
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.Nm
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reads all the interface routes from the routing table and advertises
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them as on-link prefixes.
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.Pp
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.Nm
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also watches the routing table.
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If an interface direct route is
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added on an advertising interface and no static prefixes are
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specified by the configuration file,
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.Nm
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adds the corresponding prefix to its advertising list.
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.Pp
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Similarly, when an interface direct route is deleted,
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.Nm
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will start advertising the prefixes with zero valid and preferred
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lifetimes to help the receiving hosts switch to a new prefix when
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renumbering.
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Note, however, that the zero valid lifetime cannot invalidate the
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autoconfigured addresses at a receiving host immediately.
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According to the specification, the host will retain the address
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for a certain period, which will typically be two hours.
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The zero lifetimes rather intend to make the address deprecated,
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indicating that a new non-deprecated address should be used as the
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source address of a new connection.
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This behavior will last for two hours.
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Then
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.Nm
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will completely remove the prefix from the advertising list,
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and succeeding advertisements will not contain the prefix information.
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.Pp
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Moreover, if the status of an advertising interface changes,
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.Nm
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will start or stop sending router advertisements according
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to the latest status.
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.Pp
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The
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.Fl s
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option may be used to disable this behavior;
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.Nm
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will not watch the routing table and the whole functionality described
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above will be suppressed.
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.Pp
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Basically, hosts MUST NOT send Router Advertisement messages at any
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time (RFC 2461, Section 6.2.3).
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However, it would sometimes be useful to allow hosts to advertise some
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parameters such as prefix information and link MTU.
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Thus,
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.Nm
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can be invoked if router lifetime is explicitly set zero on every
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advertising interface.
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.Pp
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The command line options are:
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.Bl -tag -width indent
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.\"
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.It Fl c
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Specify an alternate location,
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.Ar configfile ,
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for the configuration file.
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By default,
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.Pa /etc/rtadvd.conf
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is used.
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.It Fl d
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Print debugging information.
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.It Fl D
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Even more debugging information is printed.
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.It Fl f
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Foreground mode (useful when debugging).
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.It Fl M
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Specify an interface to join the all-routers site-local multicast group.
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By default,
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.Nm
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tries to join the first advertising interface appeared in the command
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line.
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This option has meaning only with the
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.Fl R
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option, which enables routing renumbering protocol support.
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.\".It Fl m
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.\"Enables mobile IPv6 support.
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.\"This changes the content of router advertisement option, as well as
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.\"permitted configuration directives.
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.It Fl R
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Accept router renumbering requests.
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If you enable it, certain IPsec setup is suggested for security reasons.
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On KAME-based systems,
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.Xr rrenumd 8
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generates router renumbering request packets.
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This option is currently disabled, and is ignored by
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.Nm
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with a warning message.
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.It Fl s
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Do not add or delete prefixes dynamically.
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Only statically configured prefixes, if any, will be advertised.
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.El
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.Pp
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Upon receipt of signal
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.Dv SIGUSR1 ,
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.Nm
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will dump the current internal state into
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.Pa /var/run/rtadvd.dump .
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.Pp
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Use
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.Dv SIGTERM
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to kill
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.Nm
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gracefully.
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In this case,
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.Nm
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will transmit router advertisement with router lifetime 0
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to all the interfaces
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(in accordance with RFC2461 6.2.5).
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.Sh DIAGNOSTICS
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.Ex -std
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.Sh FILES
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.Bl -tag -width Pa -compact
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.It Pa /etc/rtadvd.conf
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The default configuration file.
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.It Pa /var/run/rtadvd.pid
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contains the pid of the currently running
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.Nm .
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.It Pa /var/run/rtadvd.dump
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in which
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.Nm
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dumps its internal state.
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.El
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.Sh SEE ALSO
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.Xr rtadvd.conf 5 ,
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.Xr rrenumd 8 ,
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.Xr rtsol 8
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.Sh HISTORY
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The
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.Nm
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command first appeared in WIDE Hydrangea IPv6 protocol stack kit.
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.Sh CAVEAT
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There used to be some text that recommended users not to let
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.Nm
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advertise Router Advertisement messages on an upstream link to avoid
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undesirable
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.Xr icmp6 4
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redirect messages.
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However, based on the later discussion in the IETF ipng working group,
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all routers should rather advertise the messages regardless of
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the network topology, in order to ensure reachability.
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