1.\" $NetBSD: rtadvd.8,v 1.24 2012/12/13 21:49:38 wiz Exp $ 2.\" $KAME: rtadvd.8,v 1.24 2002/05/31 16:16:08 jinmei Exp $ 3.\" 4.\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5.\" All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the project nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.Dd December 13, 2006 32.Dt RTADVD 8 33.Os 34.Sh NAME 35.Nm rtadvd 36.Nd router advertisement daemon 37.Sh SYNOPSIS 38.Nm 39.Op Fl DdfRs 40.Op Fl c Ar configfile 41.Op Fl M Ar ifname 42.Ar interface ... 43.Sh DESCRIPTION 44.Nm 45sends router advertisement packets to the specified interfaces. 46.Pp 47The program will daemonize itself on invocation. 48It will then send router advertisement packets periodically, as well 49as in response to router solicitation messages sent by end hosts. 50.Pp 51Router advertisements can be configured on a per-interface basis, as 52described in 53.Xr rtadvd.conf 5 . 54.Pp 55If there is no configuration file entry for an interface, 56or if the configuration file does not exist at all, 57.Nm 58sets all the parameters to their default values. 59In particular, 60.Nm 61reads all the interface routes from the routing table and advertises 62them as on-link prefixes. 63.Pp 64.Nm 65also watches the routing table. 66If an interface direct route is 67added on an advertising interface and no static prefixes are 68specified by the configuration file, 69.Nm 70adds the corresponding prefix to its advertising list. 71.Pp 72Similarly, when an interface direct route is deleted, 73.Nm 74will start advertising the prefixes with zero valid and preferred 75lifetimes to help the receiving hosts switch to a new prefix when 76renumbering. 77Note, however, that the zero valid lifetime cannot invalidate the 78autoconfigured addresses at a receiving host immediately. 79According to the specification, the host will retain the address 80for a certain period, which will typically be two hours. 81The zero lifetimes rather intend to make the address deprecated, 82indicating that a new non-deprecated address should be used as the 83source address of a new connection. 84This behavior will last for two hours. 85Then 86.Nm 87will completely remove the prefix from the advertising list, 88and succeeding advertisements will not contain the prefix information. 89.Pp 90Moreover, if the status of an advertising interface changes, 91.Nm 92will start or stop sending router advertisements according 93to the latest status. 94.Pp 95The 96.Fl s 97option may be used to disable this behavior; 98.Nm 99will not watch the routing table and the whole functionality described 100above will be suppressed. 101.Pp 102Basically, hosts MUST NOT send Router Advertisement messages at any 103time (RFC 2461, Section 6.2.3). 104However, it would sometimes be useful to allow hosts to advertise some 105parameters such as prefix information and link MTU. 106Thus, 107.Nm 108can be invoked if router lifetime is explicitly set to zero on every 109advertising interface. 110.Pp 111The command line options are: 112.Bl -tag -width indent 113.\" 114.It Fl c Ar configfile 115Specify an alternate location, 116.Ar configfile , 117for the configuration file. 118By default, 119.Pa /etc/rtadvd.conf 120is used. 121.It Fl D 122Even more debugging information than that offered by the 123.Fl d 124option is printed. 125.It Fl d 126Print debugging information. 127.It Fl f 128Foreground mode (useful when debugging). 129Log messages will be dumped to stderr when this option is specified. 130.It Fl M Ar ifname 131Specify an interface to join the all-routers site-local multicast group. 132By default, 133.Nm 134tries to join the first advertising interface appearing on the command 135line. 136This option has meaning only with the 137.Fl R 138option, which enables routing renumbering protocol support. 139.\".It Fl m 140.\"Enables mobile IPv6 support. 141.\"This changes the content of router advertisement option, as well as 142.\"permitted configuration directives. 143.It Fl R 144Accept router renumbering requests. 145If you enable it, an 146.Xr ipsec 4 147setup is suggested for security reasons. 148.\"On KAME-based systems, 149.\".Xr rrenumd 8 150.\"generates router renumbering request packets. 151This option is currently disabled, and is ignored by 152.Nm 153with a warning message. 154.It Fl s 155Do not add or delete prefixes dynamically. 156Only statically configured prefixes, if any, will be advertised. 157.El 158.Pp 159Use 160.Dv SIGHUP 161to reload the configuration file 162.Pa /etc/rtadvd.conf . 163If an invalid parameter is found in the configuration file upon the reload, the 164entry will be ignored and the old configuration will be used. 165When parameters in an existing entry are updated, 166.Nm 167will send Router Advertisement messages with the old configuration but zero 168router lifetime to the interface first, and then start to send a new message. 169.Pp 170Upon receipt of signal 171.Dv SIGUSR1 , 172.Nm 173will dump the current internal state into 174.Pa /var/run/rtadvd.dump . 175.Pp 176Use 177.Dv SIGTERM 178to kill 179.Nm 180gracefully. 181In this case, 182.Nm 183will transmit router advertisement with router lifetime 0 184to all the interfaces 185.Pq in accordance with RFC 2461 6.2.5 . 186.Sh FILES 187.Bl -tag -width /var/run/rtadvd.dumpXX -compact 188.It Pa /etc/rtadvd.conf 189The default configuration file. 190.It Pa /var/run/rtadvd.pid 191Contains the PID of the currently running 192.Nm . 193.It Pa /var/run/rtadvd.dump 194The file in which 195.Nm 196dumps its internal state. 197.El 198.Sh EXIT STATUS 199.Ex -std rtadvd 200.Sh SEE ALSO 201.Xr rtadvd.conf 5 , 202.Xr rtsol 8 203.Sh HISTORY 204The 205.Nm 206command first appeared in the WIDE Hydrangea IPv6 protocol stack kit. 207.Sh BUGS 208There used to be some text that recommended users not to let 209.Nm 210advertise Router Advertisement messages on an upstream link to avoid 211undesirable 212.Xr icmp6 4 213redirect messages. 214However, based on later discussion in the IETF IPng working group, 215all routers should rather advertise the messages regardless of 216the network topology, in order to ensure reachability. 217