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 43The 44.Nm 45utility sends router advertisement packets to the specified 46.Ar interfaces . 47.Pp 48The program will daemonize itself on invocation. 49It will then send router advertisement packets periodically, as well 50as in response to router solicitation messages sent by end hosts. 51.Pp 52Router advertisements can be configured on a per-interface basis, as 53described in 54.Xr rtadvd.conf 5 . 55.Pp 56If there is no configuration file entry for an interface, 57or if the configuration file does not exist altogether, 58.Nm 59sets all the parameters to their default values. 60In particular, 61.Nm 62reads all the interface routes from the routing table and advertises 63them as on-link prefixes. 64.Pp 65The 66.Nm 67utility also watches the routing table. 68If an interface direct route is 69added on an advertising interface and no static prefixes are 70specified by the configuration file, 71.Nm 72adds the corresponding prefix to its advertising list. 73.Pp 74Similarly, when an interface direct route is deleted, 75.Nm 76will start advertising the prefixes with zero valid and preferred 77lifetimes to help the receiving hosts switch to a new prefix when 78renumbering. 79Note, however, that the zero valid lifetime cannot invalidate the 80autoconfigured addresses at a receiving host immediately. 81According to the specification, the host will retain the address 82for a certain period, which will typically be two hours. 83The zero lifetimes rather intend to make the address deprecated, 84indicating that a new non-deprecated address should be used as the 85source address of a new connection. 86This behavior will last for two hours. 87Then 88.Nm 89will completely remove the prefix from the advertising list, 90and succeeding advertisements will not contain the prefix information. 91.Pp 92Moreover, if the status of an advertising interface changes, 93.Nm 94will start or stop sending router advertisements according 95to the latest status. 96.Pp 97The 98.Fl s 99option may be used to disable this behavior; 100.Nm 101will not watch the routing table and the whole functionality described 102above will be suppressed. 103.Pp 104Basically, hosts MUST NOT send Router Advertisement messages at any 105time (RFC 2461, Section 6.2.3). 106However, it would sometimes be useful to allow hosts to advertise some 107parameters such as prefix information and link MTU. 108Thus, 109.Nm 110can be invoked if router lifetime is explicitly set zero on every 111advertising interface. 112.Pp 113The command line options are: 114.Bl -tag -width indent 115.\" 116.It Fl c 117Specify an alternate location, 118.Ar configfile , 119for the configuration file. 120By default, 121.Pa /etc/rtadvd.conf 122is used. 123.It Fl d 124Print debugging information. 125.It Fl D 126Even more debugging information is printed. 127.It Fl f 128Foreground mode (useful when debugging). 129.It Fl M 130Specify an interface to join the all-routers site-local multicast group. 131By default, 132.Nm 133tries to join the first advertising interface appeared in the command 134line. 135This option has meaning only with the 136.Fl R 137option, which enables routing renumbering protocol support. 138.\".It Fl m 139.\"Enables mobile IPv6 support. 140.\"This changes the content of router advertisement option, as well as 141.\"permitted configuration directives. 142.It Fl R 143Accept router renumbering requests. 144If you enable it, certain IPsec setup is suggested for security reasons. 145On KAME-based systems, 146.Xr rrenumd 8 147generates router renumbering request packets. 148This option is currently disabled, and is ignored by 149.Nm 150with a warning message. 151.It Fl s 152Do not add or delete prefixes dynamically. 153Only statically configured prefixes, if any, will be advertised. 154.El 155.Pp 156Upon receipt of signal 157.Dv SIGUSR1 , 158.Nm 159will dump the current internal state into 160.Pa /var/run/rtadvd.dump . 161.Pp 162Use 163.Dv SIGTERM 164to kill 165.Nm 166gracefully. 167In this case, 168.Nm 169will transmit router advertisement with router lifetime 0 170to all the interfaces 171(in accordance with RFC2461 6.2.5). 172.Sh DIAGNOSTICS 173.Ex -std 174.Sh FILES 175.Bl -tag -width Pa -compact 176.It Pa /etc/rtadvd.conf 177The default configuration file. 178.It Pa /var/run/rtadvd.pid 179contains the pid of the currently running 180.Nm . 181.It Pa /var/run/rtadvd.dump 182in which 183.Nm 184dumps its internal state. 185.El 186.Sh SEE ALSO 187.Xr rtadvd.conf 5 , 188.Xr rrenumd 8 , 189.Xr rtsol 8 190.Sh HISTORY 191The 192.Nm 193utility first appeared in WIDE Hydrangea IPv6 protocol stack kit. 194.Sh CAVEAT 195There used to be some text that recommended users not to let 196.Nm 197advertise Router Advertisement messages on an upstream link to avoid 198undesirable 199.Xr icmp6 4 200redirect messages. 201However, based on the later discussion in the IETF ipng working group, 202all routers should rather advertise the messages regardless of 203the network topology, in order to ensure reachability. 204