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.\" $FreeBSD$ 31.\" 32.Dd December 22, 2010 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.Op Fl F Ar dumpfile 43.Op Fl p Ar pidfile 44.Ar interface ... 45.Sh DESCRIPTION 46.Nm 47sends router advertisement packets to the specified 48.Ar interfaces . 49.Pp 50The program will daemonize itself on invocation. 51It will then send router advertisement packets periodically, as well 52as in response to router solicitation messages sent by end hosts. 53.Pp 54Router advertisements can be configured on a per-interface basis, as 55described in 56.Xr rtadvd.conf 5 . 57.Pp 58If there is no configuration file entry for an interface, 59or if the configuration file does not exist altogether, 60.Nm 61sets all the parameters to their default values. 62In particular, 63.Nm 64reads all the interface routes from the routing table and advertises 65them as on-link prefixes. 66.Pp 67.Nm 68also 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). 130Log messages will be dumped to stderr when this option is specified. 131.It Fl F 132Specify an alternative file in which to dump internal states when 133.Nm 134receives signal 135.Dv SIGUSR1 . 136The default is 137.Pa /var/run/rtadvd.dump . 138.It Fl M 139Specify an interface to join the all-routers site-local multicast group. 140By default, 141.Nm 142tries to join the first advertising interface appearing on the command 143line. 144This option has meaning only with the 145.Fl R 146option, which enables routing renumbering protocol support. 147.It Fl p 148Specify an alternative file in which to store the process ID. 149The default is 150.Pa /var/run/rtadvd.pid. 151.It Fl R 152Accept router renumbering requests. 153If you enable it, certain IPsec setup is suggested for security reasons. 154This option is currently disabled, and is ignored by 155.Nm 156with a warning message. 157.It Fl s 158Do not add or delete prefixes dynamically. 159Only statically configured prefixes, if any, will be advertised. 160.El 161.Pp 162Upon receipt of signal 163.Dv SIGUSR1 , 164.Nm 165will dump the current internal state into 166.Pa /var/run/rtadvd.dump 167or the file specified with option 168.Fl F . 169.Pp 170Use 171.Dv SIGTERM 172to kill 173.Nm 174gracefully. 175In this case, 176.Nm 177will transmit router advertisement with router lifetime 0 178to all the interfaces 179.Pq in accordance with RFC2461 6.2.5 . 180.Sh FILES 181.Bl -tag -width Pa -compact 182.It Pa /etc/rtadvd.conf 183The default configuration file. 184.It Pa /var/run/rtadvd.pid 185The default process ID file. 186.It Pa /var/run/rtadvd.dump 187The default file in which 188.Nm 189dumps its internal state. 190.El 191.Sh EXIT STATUS 192.Ex -std 193.Sh SEE ALSO 194.Xr rtadvd.conf 5 , 195.Xr rtsol 8 196.Sh HISTORY 197The 198.Nm 199command first appeared in the WIDE Hydrangea IPv6 protocol stack kit. 200.Sh BUGS 201There used to be some text that recommended users not to let 202.Nm 203advertise Router Advertisement messages on an upstream link to avoid 204undesirable 205.Xr icmp6 4 206redirect messages. 207However, based on the later discussion in the IETF ipng working group, 208all routers should rather advertise the messages regardless of 209the network topology, in order to ensure reachability. 210