1.\" $FreeBSD$ 2.\" $KAME: rtadvd.8,v 1.17 2001/02/04 05:34:38 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 May 17, 1998 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 dDfMRs 40.Op Fl c Ar configfile 41.Ar interface ... 42.Sh DESCRIPTION 43.Nm 44sends router advertisement packets to the specified 45.Ar 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 altogether, 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 zero on every 109advertising interface. 110.Pp 111The command line options are: 112.Bl -tag -width indent 113.\" 114.It Fl c 115Specify an alternate location, 116.Ar configfile , 117for the configuration file. 118By default, 119.Pa /etc/rtadvd.conf 120is used. 121.It Fl d 122Print debugging information. 123.It Fl D 124Even more debugging information is printed. 125.It Fl f 126Foreground mode (useful when debugging). 127.It Fl M 128Specify an interface to join the all-routers site-local multicast group. 129By default, 130.Nm 131tries to join the first advertising interface appeared in the command 132line. 133This option has meaning only with the 134.Fl R 135option, which enables routing renumbering protocol support. 136.\".It Fl m 137.\"Enables mobile IPv6 support. 138.\"This changes the content of router advertisement option, as well as 139.\"permitted configuration directives. 140.It Fl R 141Accept router renumbering requests. 142If you enable it, certain IPsec setup is suggested for security reasons. 143On KAME-based systems, 144.Xr rrenumd 8 145generates router renumbering request packets. 146This option is currently disabled, and is ignored by 147.Nm 148with a warning message. 149.It Fl s 150Do not add or delete prefixes dynamically. 151Only statically configured prefixes, if any, will be advertised. 152.El 153.Pp 154Upon receipt of signal 155.Dv SIGUSR1 , 156.Nm 157will dump the current internal state into 158.Pa /var/run/rtadvd.dump . 159.Pp 160Use 161.Dv SIGTERM 162to kill 163.Nm 164gracefully. 165In this case, 166.Nm 167will transmit router advertisement with router lifetime 0 168to all the interfaces 169(in accordance with RFC2461 6.2.5). 170.Sh DIAGNOSTICS 171.Ex -std 172.Sh FILES 173.Bl -tag -width Pa -compact 174.It Pa /etc/rtadvd.conf 175The default configuration file. 176.It Pa /var/run/rtadvd.pid 177contains the pid of the currently running 178.Nm . 179.It Pa /var/run/rtadvd.dump 180in which 181.Nm 182dumps its internal state. 183.El 184.Sh SEE ALSO 185.Xr rtadvd.conf 5 , 186.Xr rrenumd 8 , 187.Xr rtsol 8 188.Sh HISTORY 189The 190.Nm 191command first appeared in WIDE Hydrangea IPv6 protocol stack kit. 192.Sh CAVEAT 193There used to be some text that recommended users not to let 194.Nm 195advertise Router Advertisement messages on an upstream link to avoid 196undesirable 197.Xr icmp6 4 198redirect messages. 199However, based on the later discussion in the IETF ipng working group, 200all routers should rather advertise the messages regardless of 201the network topology, in order to ensure reachability. 202