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