1.\" $NetBSD: rtadvd.8,v 1.26 2017/11/06 15:15:04 christos Exp $ 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 November 6, 2017 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 DdfRs 40.Op Fl c Ar configfile 41.Op Fl M Ar ifname 42.Op Fl p Ar pidfile 43.Ar interface ... 44.Sh DESCRIPTION 45.Nm 46sends router advertisement packets to the specified 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 at all, 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 to zero on every 110advertising interface. 111.Pp 112The command line options are: 113.Bl -tag -width indent 114.\" 115.It Fl c Ar configfile 116Specify an alternate location, 117.Ar configfile , 118for the configuration file. 119By default, 120.Pa /etc/rtadvd.conf 121is used. 122.It Fl D 123Instead of printing errors using 124.Xr syslog 3 125send them to 126.Dv stderr . 127Also when 128.Xr poll 2 129fails, exit instead of retrying. 130.It Fl d 131Print debugging information. 132Repeating this option, adds more verbose debugging. 133.It Fl f 134Foreground mode (useful when debugging). 135Log messages will be dumped to stderr when this option is specified. 136.It Fl M Ar ifname 137Specify an interface to join the all-routers site-local multicast group. 138By default, 139.Nm 140tries to join the first advertising interface appearing on the command 141line. 142This option has meaning only with the 143.Fl R 144option, which enables routing renumbering protocol support. 145.\".It Fl m 146.\"Enables mobile IPv6 support. 147.\"This changes the content of router advertisement option, as well as 148.\"permitted configuration directives. 149.It Fl p Ar pidfile 150Specify an alternate location, 151.Ar pidfile , 152for the PID file. 153By default, 154.Pa /var/run/rtadvd.pid 155is used. 156.It Fl R 157Accept router renumbering requests. 158If you enable it, an 159.Xr ipsec 4 160setup is suggested for security reasons. 161.\"On KAME-based systems, 162.\".Xr rrenumd 8 163.\"generates router renumbering request packets. 164This option is currently disabled, and is ignored by 165.Nm 166with a warning message. 167.It Fl s 168Do not add or delete prefixes dynamically. 169Only statically configured prefixes, if any, will be advertised. 170.El 171.Pp 172Use 173.Dv SIGHUP 174to reload the configuration file 175.Pa /etc/rtadvd.conf . 176If an invalid parameter is found in the configuration file upon the reload, the 177entry will be ignored and the old configuration will be used. 178When parameters in an existing entry are updated, 179.Nm 180will send Router Advertisement messages with the old configuration but zero 181router lifetime to the interface first, and then start to send a new message. 182.Pp 183Upon receipt of signal 184.Dv SIGUSR1 , 185.Nm 186will dump the current internal state into 187.Pa /var/run/rtadvd.dump . 188.Pp 189Use 190.Dv SIGTERM 191to kill 192.Nm 193gracefully. 194In this case, 195.Nm 196will transmit router advertisement with router lifetime 0 197to all the interfaces 198.Pq in accordance with RFC 2461 6.2.5 . 199.Sh FILES 200.Bl -tag -width /var/run/rtadvd.dumpXX -compact 201.It Pa /etc/rtadvd.conf 202The default configuration file. 203.It Pa /var/run/rtadvd.pid 204Contains the PID of the currently running 205.Nm . 206.It Pa /var/run/rtadvd.dump 207The file in which 208.Nm 209dumps its internal state. 210.El 211.Sh EXIT STATUS 212.Ex -std rtadvd 213.Sh SEE ALSO 214.Xr rtadvd.conf 5 , 215.Xr rtsol 8 216.Sh HISTORY 217The 218.Nm 219command first appeared in the WIDE Hydrangea IPv6 protocol stack kit. 220.Sh BUGS 221There used to be some text that recommended users not to let 222.Nm 223advertise Router Advertisement messages on an upstream link to avoid 224undesirable 225.Xr icmp6 4 226redirect messages. 227However, based on later discussion in the IETF IPng working group, 228all routers should rather advertise the messages regardless of 229the network topology, in order to ensure reachability. 230