1.\" $KAME: rtadvd.8,v 1.24 2002/05/31 16:16:08 jinmei Exp $ 2.\" 3.\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the project nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" $FreeBSD: stable/10/usr.sbin/rtadvd/rtadvd.8 247270 2013-02-25 16:47:09Z des $ 31.\" 32.Dd April 21, 2018 33.Dt RTADVD 8 34.Os 35.Sh NAME 36.Nm rtadvd 37.Nd router advertisement daemon 38.Sh SYNOPSIS 39.Nm 40.Op Fl dDfRs 41.Op Fl c Ar configfile 42.Op Fl C Ar ctlsock 43.Op Fl M Ar ifname 44.Op Fl p Ar pidfile 45.Op Ar interface ... 46.Sh DESCRIPTION 47.Nm 48sends router advertisement packets to the specified 49.Ar interfaces . 50If no interfaces are specified, 51.Nm 52will still run, but will not advertise any routes until interfaces are 53added using 54.Xr rtadvctl 8 . 55.Pp 56The program will daemonize itself on invocation. 57It will then send router advertisement packets periodically, as well 58as in response to router solicitation messages sent by end hosts. 59.Pp 60Router advertisements can be configured on a per-interface basis, as 61described in 62.Xr rtadvd.conf 5 . 63.Pp 64If there is no configuration file entry for an interface, 65or if the configuration file does not exist altogether, 66.Nm 67sets all the parameters to their default values. 68In particular, 69.Nm 70reads all the interface routes from the routing table and advertises 71them as on-link prefixes. 72.Pp 73.Nm 74also watches the routing table. 75If an interface direct route is 76added on an advertising interface and no static prefixes are 77specified by the configuration file, 78.Nm 79adds the corresponding prefix to its advertising list. 80.Pp 81Similarly, when an interface direct route is deleted, 82.Nm 83will start advertising the prefixes with zero valid and preferred 84lifetimes to help the receiving hosts switch to a new prefix when 85renumbering. 86Note, however, that the zero valid lifetime cannot invalidate the 87autoconfigured addresses at a receiving host immediately. 88According to the specification, the host will retain the address 89for a certain period, which will typically be two hours. 90The zero lifetimes rather intend to make the address deprecated, 91indicating that a new non-deprecated address should be used as the 92source address of a new connection. 93This behavior will last for two hours. 94Then 95.Nm 96will completely remove the prefix from the advertising list, 97and succeeding advertisements will not contain the prefix information. 98.Pp 99Moreover, if the status of an advertising interface changes, 100.Nm 101will start or stop sending router advertisements according 102to the latest status. 103.Pp 104The 105.Fl s 106option may be used to disable this behavior; 107.Nm 108will not watch the routing table and the whole functionality described 109above will be suppressed. 110.Pp 111Basically, hosts MUST NOT send Router Advertisement messages at any 112time (RFC 4861, Section 6.2.3). 113However, it would sometimes be useful to allow hosts to advertise some 114parameters such as prefix information and link MTU. 115Thus, 116.Nm 117can be invoked if router lifetime is explicitly set zero on every 118advertising interface. 119.Pp 120The command line options are: 121.Bl -tag -width indent 122.\" 123.It Fl c 124Specify an alternate location, 125.Ar configfile , 126for the configuration file. 127By default, 128.Pa /etc/rtadvd.conf 129is used. 130.It Fl C 131Specify an alternate location for the control socket used by 132.Xr rtadvctl 8 . 133The default is 134.Pa /var/run/rtadvd.sock . 135.It Fl d 136Print debugging information. 137.It Fl D 138Even more debugging information is printed. 139.It Fl f 140Foreground mode (useful when debugging). 141Log messages will be dumped to stderr when this option is specified. 142.It Fl M 143Specify an interface to join the all-routers site-local multicast group. 144By default, 145.Nm 146tries to join the first advertising interface appearing on the command 147line. 148This option has meaning only with the 149.Fl R 150option, which enables routing renumbering protocol support. 151.It Fl p 152Specify an alternative file in which to store the process ID. 153The default is 154.Pa /var/run/rtadvd.pid . 155.It Fl R 156Accept router renumbering requests. 157This option is currently disabled, and is ignored by 158.Nm 159with a warning message. 160.It Fl s 161Do not add or delete prefixes dynamically. 162Only statically configured prefixes, if any, will be advertised. 163.El 164.Pp 165Use 166.Dv SIGHUP 167to reload the configuration file 168.Pa /etc/rtadvd.conf . 169If an invalid parameter is found in the configuration file upon the reload, 170the entry will be ignored and the old configuration will be used. 171When parameters in an existing entry are updated, 172.Nm 173will send Router Advertisement messages with the old configuration but 174zero router lifetime to the interface first, and then start to send a new 175message. 176.Pp 177Use 178.Dv SIGTERM 179to kill 180.Nm 181gracefully. 182In this case, 183.Nm 184will transmit router advertisement with router lifetime 0 185to all the interfaces 186.Pq in accordance with RFC 4861 6.2.5 . 187.Sh FILES 188.Bl -tag -width Pa -compact 189.It Pa /etc/rtadvd.conf 190The default configuration file. 191.It Pa /var/run/rtadvd.pid 192The default process ID file. 193.El 194.Sh EXIT STATUS 195.Ex -std 196.Sh SEE ALSO 197.Xr rtadvd.conf 5 , 198.Xr rtadvctl 8 , 199.Xr rtsol 8 200.Rs 201.%A Thomas Narten 202.%A Erik Nordmark 203.%A W. A. Simpson 204.%A Hesham Soliman 205.%T Neighbor Discovery for IP version 6 (IPv6) 206.%R RFC 4861 207.Re 208.Rs 209.%A Thomas Narten 210.%A Erik Nordmark 211.%A W. A. Simpson 212.%T Neighbor Discovery for IP version 6 (IPv6) 213.%R RFC 2461 (obsoleted by RFC 4861) 214.Re 215.Rs 216.%A Richard Draves 217.%T Default Router Preferences and More-Specific Routes 218.%R draft-ietf-ipngwg-router-selection-xx.txt 219.Re 220.Rs 221.%A J. Jeong 222.%A S. Park 223.%A L. Beloeil 224.%A S. Madanapalli 225.%T IPv6 Router Advertisement Options for DNS Configuration 226.%R RFC 6106 227.Re 228.Sh HISTORY 229The 230.Nm 231command first appeared in the WIDE Hydrangea IPv6 protocol stack kit. 232.Sh BUGS 233There used to be some text that recommended users not to let 234.Nm 235advertise Router Advertisement messages on an upstream link to avoid 236undesirable 237.Xr icmp6 4 238redirect messages. 239However, based on the later discussion in the IETF ipng working group, 240all routers should rather advertise the messages regardless of 241the network topology, in order to ensure reachability. 242