1.\" $FreeBSD$ 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 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). 127Log messages will be dumped to stderr when this option is specified. 128.It Fl M 129Specify an interface to join the all-routers site-local multicast group. 130By default, 131.Nm 132tries to join the first advertising interface appearing on the command 133line. 134This option has meaning only with the 135.Fl R 136option, which enables routing renumbering protocol support. 137.It Fl R 138Accept router renumbering requests. 139If you enable it, certain IPsec setup is suggested for security reasons. 140This option is currently disabled, and is ignored by 141.Nm 142with a warning message. 143.It Fl s 144Do not add or delete prefixes dynamically. 145Only statically configured prefixes, if any, will be advertised. 146.El 147.Pp 148Upon receipt of signal 149.Dv SIGUSR1 , 150.Nm 151will dump the current internal state into 152.Pa /var/run/rtadvd.dump . 153.Pp 154Use 155.Dv SIGTERM 156to kill 157.Nm 158gracefully. 159In this case, 160.Nm 161will transmit router advertisement with router lifetime 0 162to all the interfaces 163.Pq in accordance with RFC2461 6.2.5 . 164.Sh RETURN VALUES 165The 166.Nm 167program exits 0 on success, and >0 on failures. 168.Sh FILES 169.Bl -tag -width Pa -compact 170.It Pa /etc/rtadvd.conf 171The default configuration file. 172.It Pa /var/run/rtadvd.pid 173contains the pid of the currently running 174.Nm . 175.It Pa /var/run/rtadvd.dump 176The file in which 177.Nm 178dumps its internal state. 179.El 180.Sh SEE ALSO 181.Xr rtadvd.conf 5 , 182.Xr rtsol 8 183.Sh HISTORY 184The 185.Nm 186command first appeared in the WIDE Hydrangea IPv6 protocol stack kit. 187.Sh BUGS 188There used to be some text that recommended users not to let 189.Nm 190advertise Router Advertisement messages on an upstream link to avoid 191undesirable 192.Xr icmp6 4 193redirect messages. 194However, based on the later discussion in the IETF ipng working group, 195all routers should rather advertise the messages regardless of 196the network topology, in order to ensure reachability. 197