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 1.17 2001/02/04 05:34:38 jinmei Exp $
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  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
  43 .Nm
  44 sends router advertisement packets to the specified
  45 .Ar interfaces .
  46 .Pp
  47 The program will daemonize itself on invocation.
  48 It will then send router advertisement packets periodically, as well
  49 as in response to router solicitation messages sent by end hosts.
  50 .Pp
  51 Router advertisements can be configured on a per-interface basis, as
  52 described in
  53 .Xr rtadvd.conf 5 .
  54 .Pp
  55 If there is no configuration file entry for an interface,
  56 or if the configuration file does not exist altogether,
  57 .Nm
  58 sets all the parameters to their default values.
  59 In particular,
  60 .Nm
  61 reads all the interface routes from the routing table and advertises
  62 them as on-link prefixes.
  63 .Pp
  64 .Nm
  65 also watches the routing table.
  66 By default, if an interface direct route is
  67 added/deleted on an advertising interface and no static prefixes are
  68 specified by the configuration file,
  69 .Nm
  70 adds/deletes the corresponding prefix to/from its advertising list,
  71 respectively.
  72 The
  73 .Fl s
  74 option may be used to disable this behavior.
  75 Moreover, if the status of an advertising interface changes,
  76 .Nm
  77 will start or stop sending router advertisements according
  78 to the latest status.
  79 .Pp
  80 Basically, hosts MUST NOT send Router Advertisement messages at any
  81 time (RFC 2461, Section 6.2.3).
  82 However, it would sometimes be useful to allow hosts to advertise some
  83 parameters such as prefix information and link MTU.
  84 Thus,
  85 .Nm
  86 can be invoked if router lifetime is explicitly set zero on every
  87 advertising interface.
  88 .Pp
  89 The command line options are:
  90 .Bl -tag -width indent
  91 .\"
  92 .It Fl c
  93 Specify an alternate location,
  94 .Ar configfile ,
  95 for the configuration file.
  96 By default,
  97 .Pa /etc/rtadvd.conf
  98 is used.
  99 .It Fl d
 100 Print debugging information.
 101 .It Fl D
 102 Even more debugging information is printed.
 103 .It Fl f
 104 Foreground mode (useful when debugging).
 105 .It Fl M
 106 Specify an interface to join the all-routers site-local multicast group.
 107 By default,
 108 .Nm
 109 tries to join the first advertising interface appeared in the command
 110 line.
 111 This option has meaning only with the
 112 .Fl R
 113 option, which enables routing renumbering protocol support.
 114 .\".It Fl m
 115 .\"Enables mobile IPv6 support.
 116 .\"This changes the content of router advertisement option, as well as
 117 .\"permitted configuration directives.
 118 .It Fl R
 119 Accept router renumbering requests.
 120 If you enable it, certain IPsec setup is suggested for security reasons.
 121 On KAME-based systems,
 122 .Xr rrenumd 8
 123 generates router renumbering request packets.
 124 This option is currently disabled, and is ignored by
 125 .Nm
 126 with a warning message.
 127 .It Fl s
 128 Do not add or delete prefixes dynamically.
 129 Only statically configured prefixes, if any, will be advertised.
 130 .El
 131 .Pp
 132 Upon receipt of signal
 133 .Dv SIGUSR1 ,
 134 .Nm
 135 will dump the current internal state into
 136 .Pa /var/run/rtadvd.dump .
 137 .Pp
 138 Use
 139 .Dv SIGTERM
 140 to kill
 141 .Nm
 142 gracefully.
 143 In this case,
 144 .Nm
 145 will transmit router advertisement with router lifetime 0
 146 to all the interfaces
 147 (in accordance with RFC2461 6.2.5).
 148 .Sh DIAGNOSTICS
 149 .Ex -std
 150 .Sh FILES
 151 .Bl -tag -width Pa -compact
 152 .It Pa /etc/rtadvd.conf
 153 The default configuration file.
 154 .It Pa /var/run/rtadvd.pid
 155 contains the pid of the currently running
 156 .Nm .
 157 .It Pa /var/run/rtadvd.dump
 158 in which
 159 .Nm
 160 dumps its internal state.
 161 .El
 162 .Sh SEE ALSO
 163 .Xr rtadvd.conf 5 ,
 164 .Xr rrenumd 8 ,
 165 .Xr rtsol 8
 166 .Sh HISTORY
 167 The
 168 .Nm
 169 command first appeared in WIDE Hydrangea IPv6 protocol stack kit.
 170 .Sh CAVEAT
 171 There used to be some text that recommended users not to let
 172 .Nm
 173 advertise Router Advertisement messages on an upstream link to avoid
 174 undesirable
 175 .Xr icmp6 4
 176 redirect messages.
 177 However, based on the later discussion in the IETF ipng working group,
 178 all routers should rather advertise the messages regardless of
 179 the network topology, in order to ensure reachability.