1.\" $FreeBSD: src/usr.sbin/rtadvd/rtadvd.8,v 1.3.2.8 2003/03/11 22:31:32 trhodes Exp $ 2.\" $DragonFly: src/usr.sbin/rtadvd/rtadvd.8,v 1.4 2007/11/23 23:16:37 swildner Exp $ 3.\" $KAME: rtadvd.8,v 1.17 2001/02/04 05:34:38 jinmei Exp $ 4.\" 5.\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6.\" All rights reserved. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. Neither the name of the project nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.Dd May 17, 1998 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 dDfMRs 41.Op Fl c Ar configfile 42.Ar interface ... 43.Sh DESCRIPTION 44The 45.Nm 46utility sends router advertisement packets to the specified 47.Ar interfaces . 48.Pp 49The program will daemonize itself on invocation. 50It will then send router advertisement packets periodically, as well 51as in response to router solicitation messages sent by end hosts. 52.Pp 53Router advertisements can be configured on a per-interface basis, as 54described in 55.Xr rtadvd.conf 5 . 56.Pp 57If there is no configuration file entry for an interface, 58or if the configuration file does not exist altogether, 59.Nm 60sets all the parameters to their default values. 61In particular, 62.Nm 63reads all the interface routes from the routing table and advertises 64them as on-link prefixes. 65.Pp 66The 67.Nm 68utility also watches the routing table. 69If an interface direct route is 70added on an advertising interface and no static prefixes are 71specified by the configuration file, 72.Nm 73adds the corresponding prefix to its advertising list. 74.Pp 75Similarly, when an interface direct route is deleted, 76.Nm 77will start advertising the prefixes with zero valid and preferred 78lifetimes to help the receiving hosts switch to a new prefix when 79renumbering. 80Note, however, that the zero valid lifetime cannot invalidate the 81autoconfigured addresses at a receiving host immediately. 82According to the specification, the host will retain the address 83for a certain period, which will typically be two hours. 84The zero lifetimes rather intend to make the address deprecated, 85indicating that a new non-deprecated address should be used as the 86source address of a new connection. 87This behavior will last for two hours. 88Then 89.Nm 90will completely remove the prefix from the advertising list, 91and succeeding advertisements will not contain the prefix information. 92.Pp 93Moreover, if the status of an advertising interface changes, 94.Nm 95will start or stop sending router advertisements according 96to the latest status. 97.Pp 98The 99.Fl s 100option may be used to disable this behavior; 101.Nm 102will not watch the routing table and the whole functionality described 103above will be suppressed. 104.Pp 105Basically, hosts MUST NOT send Router Advertisement messages at any 106time (RFC 2461, Section 6.2.3). 107However, it would sometimes be useful to allow hosts to advertise some 108parameters such as prefix information and link MTU. 109Thus, 110.Nm 111can be invoked if router lifetime is explicitly set zero on every 112advertising interface. 113.Pp 114The command line options are: 115.Bl -tag -width indent 116.\" 117.It Fl c 118Specify an alternate location, 119.Ar configfile , 120for the configuration file. 121By default, 122.Pa /etc/rtadvd.conf 123is used. 124.It Fl d 125Print debugging information. 126.It Fl D 127Even more debugging information is printed. 128.It Fl f 129Foreground mode (useful when debugging). 130.It Fl M 131Specify an interface to join the all-routers site-local multicast group. 132By default, 133.Nm 134tries to join the first advertising interface appeared in 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, certain IPsec setup is suggested for security reasons. 146On KAME-based systems, 147.Xr rrenumd 8 148generates router renumbering request packets. 149This option is currently disabled, and is ignored by 150.Nm 151with a warning message. 152.It Fl s 153Do not add or delete prefixes dynamically. 154Only statically configured prefixes, if any, will be advertised. 155.El 156.Pp 157Upon receipt of signal 158.Dv SIGUSR1 , 159.Nm 160will dump the current internal state into 161.Pa /var/run/rtadvd.dump . 162.Pp 163Use 164.Dv SIGTERM 165to kill 166.Nm 167gracefully. 168In this case, 169.Nm 170will transmit router advertisement with router lifetime 0 171to all the interfaces 172(in accordance with RFC 2461 6.2.5). 173.Sh FILES 174.Bl -tag -width Pa -compact 175.It Pa /etc/rtadvd.conf 176The default configuration file. 177.It Pa /var/run/rtadvd.pid 178contains the pid of the currently running 179.Nm . 180.It Pa /var/run/rtadvd.dump 181in which 182.Nm 183dumps its internal state. 184.El 185.Sh DIAGNOSTICS 186.Ex -std 187.Sh SEE ALSO 188.Xr rtadvd.conf 5 , 189.Xr rrenumd 8 , 190.Xr rtsol 8 191.Sh HISTORY 192The 193.Nm 194utility first appeared in WIDE Hydrangea IPv6 protocol stack kit. 195.Sh CAVEAT 196There used to be some text that recommended users not to let 197.Nm 198advertise Router Advertisement messages on an upstream link to avoid 199undesirable 200.Xr icmp6 4 201redirect messages. 202However, based on the later discussion in the IETF ipng working group, 203all routers should rather advertise the messages regardless of 204the network topology, in order to ensure reachability. 205