rtadvd.tproj/rtadvd.8

   1 .\"     $FreeBSD: src/usr.sbin/rtadvd/rtadvd.8,v 1.3.2.6 2001/08/16 15:56:30 ru 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 August 27, 2011
  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 .Op Fl F Ar dumpfile
  42 .Op Fl p Ar pidfile
  43 .Ar interface ...
  44 .Sh DESCRIPTION
  45 .Nm
  46 sends router advertisement packets to the specified
  47 .Ar interfaces .
  48 .Pp
  49 The program will daemonize itself on invocation.
  50 It will then send router advertisement packets periodically, as well
  51 as in response to router solicitation messages sent by end hosts.
  52 .Pp
  53 Router advertisements can be configured on a per-interface basis, as
  54 described in
  55 .Xr rtadvd.conf 5 .
  56 .Pp
  57 If there is no configuration file entry for an interface,
  58 or if the configuration file does not exist altogether,
  59 .Nm
  60 sets all the parameters to their default values.
  61 In particular,
  62 .Nm
  63 reads all the interface routes from the routing table and advertises
  64 them as on-link prefixes.
  65 .Pp
  66 .Nm
  67 also watches the routing table.
  68 If an interface direct route is
  69 added on an advertising interface and no static prefixes are
  70 specified by the configuration file,
  71 .Nm
  72 adds the corresponding prefix to its advertising list.
  73 .Pp
  74 Similarly, when an interface direct route is deleted,
  75 .Nm
  76 will start advertising the prefixes with zero valid and preferred
  77 lifetimes to help the receiving hosts switch to a new prefix when
  78 renumbering.
  79 Note, however, that the zero valid lifetime cannot invalidate the
  80 autoconfigured addresses at a receiving host immediately.
  81 According to the specification, the host will retain the address
  82 for a certain period, which will typically be two hours.
  83 The zero lifetimes rather intend to make the address deprecated,
  84 indicating that a new non-deprecated address should be used as the
  85 source address of a new connection.
  86 This behavior will last for two hours.
  87 Then
  88 .Nm
  89 will completely remove the prefix from the advertising list,
  90 and succeeding advertisements will not contain the prefix information.
  91 .Pp
  92 Moreover, if the status of an advertising interface changes,
  93 .Nm
  94 will start or stop sending router advertisements according
  95 to the latest status.
  96 .Pp
  97 The
  98 .Fl s
  99 option may be used to disable this behavior;
 100 .Nm
 101 will not watch the routing table and the whole functionality described
 102 above will be suppressed.
 103 .Pp
 104 Basically, hosts MUST NOT send Router Advertisement messages at any
 105 time (RFC 2461, Section 6.2.3).
 106 However, it would sometimes be useful to allow hosts to advertise some
 107 parameters such as prefix information and link MTU.
 108 Thus,
 109 .Nm
 110 can be invoked if router lifetime is explicitly set zero on every
 111 advertising interface.
 112 .Pp
 113 The command line options are:
 114 .Bl -tag -width indent
 115 .\"
 116 .It Fl c
 117 Specify an alternate location,
 118 .Ar configfile ,
 119 for the configuration file.
 120 By default,
 121 .Pa /etc/rtadvd.conf
 122 is used.
 123 .It Fl d
 124 Print debugging information.
 125 .It Fl D
 126 Even more debugging information is printed.
 127 .It Fl f
 128 Foreground mode (useful when debugging).
 129 Log messages will be dumped to stderr when this option is specified.
 130 .It Fl F
 131 Specify an alternative file in which to dump internal states when
 132 .Nm
 133 receives signal
 134 .Dv SIGUSR1 .
 135 The default is
 136 .Pa /var/run/rtadvd.dump .
 137 .It Fl M
 138 Specify an interface to join the all-routers site-local multicast group.
 139 By default,
 140 .Nm
 141 tries to join the first advertising interface appearing on the command
 142 line.
 143 This option has meaning only with the
 144 .Fl R
 145 option, which enables routing renumbering protocol support.
 146 .It Fl p
 147 Specify an alternative file in which to store the process ID.
 148 The default is
 149 .Pa /var/run/rtadvd.pid.
 150 .It Fl R
 151 Accept router renumbering requests.
 152 If you enable it, certain IPsec setup is suggested for security reasons.
 153 This option is currently disabled, and is ignored by
 154 .Nm
 155 with a warning message.
 156 .It Fl s
 157 Do not add or delete prefixes dynamically.
 158 Only statically configured prefixes, if any, will be advertised.
 159 .El
 160 .Pp
 161 Upon receipt of signal
 162 .Dv SIGUSR1 ,
 163 .Nm
 164 will dump the current internal state into
 165 .Pa /var/run/rtadvd.dump
 166 or the file specified with option
 167 .Fl F .
 168 .Pp
 169 Use
 170 .Dv SIGTERM
 171 to kill
 172 .Nm
 173 gracefully.
 174 In this case,
 175 .Nm
 176 will transmit router advertisement with router lifetime 0
 177 to all the interfaces
 178 .Pq in accordance with RFC2461 6.2.5 .
 179 .Sh FILES
 180 .Bl -tag -width Pa -compact
 181 .It Pa /etc/rtadvd.conf
 182 The default configuration file.
 183 .It Pa /var/run/rtadvd.pid
 184 The default process ID file.
 185 .It Pa /var/run/rtadvd.dump
 186 The default file in which
 187 .Nm
 188 dumps its internal state.
 189 .El
 190 .Sh EXIT STATUS
 191 .Ex -std
 192 .Sh SEE ALSO
 193 .Xr rtadvd.conf 5 ,
 194 .Xr rtsol 8
 195 .Sh HISTORY
 196 The
 197 .Nm
 198 command first appeared in the WIDE Hydrangea IPv6 protocol stack kit.
 199 .Sh BUGS
 200 There used to be some text that recommended users not to let
 201 .Nm
 202 advertise Router Advertisement messages on an upstream link to avoid
 203 undesirable
 204 .Xr icmp6 4
 205 redirect messages.
 206 However, based on the later discussion in the IETF ipng working group,
 207 all routers should rather advertise the messages regardless of
 208 the network topology, in order to ensure reachability.