1<refentry id="rdisc"> 2 3<refmeta> 4<refentrytitle>rdisc</refentrytitle> 5<manvolnum>8</manvolnum> 6<refmiscinfo>iputils-&snapshot;</refmiscinfo> 7</refmeta> 8 9<refnamediv> 10<refname>rdisc</refname> 11<refpurpose>network router discovery daemon</refpurpose> 12</refnamediv> 13 14<refsynopsisdiv> 15<cmdsynopsis> 16<command>rdisc</command> 17<arg choice="opt"><option>-abdfrstvV</option></arg> 18<arg choice="opt">-p <replaceable/preference/</arg> 19<arg choice="opt">-T <replaceable/max_interval/</arg> 20<arg choice="opt"><replaceable/send_address/</arg> 21<arg choice="opt"><replaceable/receive_address/</arg> 22</cmdsynopsis> 23</refsynopsisdiv> 24 25<refsect1><title>DESCRIPTION</title> 26<para> 27<command/rdisc/ implements client side of the ICMP router discover protocol. 28<command/rdisc/ is invoked at boot time to populate the network 29routing tables with default routes. 30</para> 31 32<para> 33<command/rdisc/ listens on the ALL_HOSTS (224.0.0.1) multicast address 34(or <replaceable/receive_address/ provided it is given) 35for ROUTER_ADVERTISE messages from routers. The received 36messages are handled by first ignoring those listed router addresses 37with which the host does not share a network. Among the remaining addresses 38the ones with the highest preference are selected as default routers 39and a default route is entered in the kernel routing table 40for each one of them. 41</para> 42 43<para> 44Optionally, <command/rdisc/ can avoid waiting for routers to announce 45themselves by sending out a few ROUTER_SOLICITATION messages 46to the ALL_ROUTERS (224.0.0.2) multicast address 47(or <replaceable/send_address/ provided it is given) 48when it is started. 49</para> 50 51<para> 52A timer is associated with each router address and the address will 53no longer be considered for inclusion in the the routing tables if the 54timer expires before a new 55<emphasis/advertise/ message is received from the router. 56The address will also be excluded from consideration if the host receives an 57<emphasis/advertise/ 58message with the preference being maximally negative. 59</para> 60 61<para> 62Server side of router discovery protocol is supported by Cisco IOS 63and by any more or less complete UNIX routing daemon, f.e <command/gated/. 64Or, <command/rdisc/ can act as responder, if compiled with -DRDISC_SERVER. 65</para> 66 67</refsect1> 68 69<refsect1><title>OPTIONS</title> 70 71<variablelist> 72 <varlistentry> 73 <term><option/-a/</term> 74 <listitem><para> 75Accept all routers independently of the preference they have in their 76<emphasis/advertise/ messages. 77Normally <command/rdisc/ only accepts (and enters in the kernel routing 78tables) the router or routers with the highest preference. 79 </para></listitem> 80 </varlistentry> 81 <varlistentry> 82 <term><option/-b/</term> 83 <listitem><para> 84Opposite to <option/-a/, i.e. install only router with the best 85preference value. It is default behaviour. 86 </para></listitem> 87 </varlistentry> 88 <varlistentry> 89 <term><option/-d/</term> 90 <listitem><para> 91Send debugging messages to syslog. 92 </para></listitem> 93 </varlistentry> 94 <varlistentry> 95 <term><option/-f/</term> 96 <listitem><para> 97Run <command/rdisc/ forever even if no routers are found. 98Normally <command/rdisc/ gives up if it has not received any 99<emphasis/advertise/ message after after soliciting three times, 100in which case it exits with a non-zero exit code. 101If <option/-f/ is not specified in the first form then 102<option/-s/ must be specified. 103 </para></listitem> 104 </varlistentry> 105 106 <varlistentry> 107 <term><option/-r/</term> 108 <listitem><para> 109Responder mode, available only if compiled with -DRDISC_SERVER. 110 </para></listitem> 111 </varlistentry> 112 113 <varlistentry> 114 <term><option/-s/</term> 115 <listitem><para> 116Send three <emphasis/solicitation/ messages initially to quickly discover 117the routers when the system is booted. 118When <option/-s/ is specified <command/rdisc/ 119exits with a non-zero exit code if it can not find any routers. 120This can be overridden with the <option/-f/ option. 121 </para></listitem> 122 </varlistentry> 123 124 <varlistentry> 125 <term><option>-p <replaceable/preference/</option></term> 126 <listitem><para> 127Set preference in advertisement. 128Available only with -r option. 129 </para></listitem> 130 </varlistentry> 131 132 <varlistentry> 133 <term><option>-T <replaceable/max_interval/</option></term> 134 <listitem><para> 135Set maximum advertisement interval in seconds. Default is 600 secs. 136Available only with -r option. 137 </para></listitem> 138 </varlistentry> 139 140 <varlistentry> 141 <term><option/-t/</term> 142 <listitem><para> 143Test mode. Do not go to background. 144 </para></listitem> 145 </varlistentry> 146 147 <varlistentry> 148 <term><option/-v/</term> 149 <listitem><para> 150Be verbose i.e. send lots of debugging messages to syslog. 151 </para></listitem> 152 </varlistentry> 153 154 <varlistentry> 155 <term><option/-V/</term> 156 <listitem><para> 157Print version and exit. 158 </para></listitem> 159 </varlistentry> 160</variablelist> 161</refsect1> 162 163<refsect1><title>HISTORY</title> 164<para> 165This program was developed by Sun Microsystems (see copyright 166notice in source file). It was ported to Linux by 167<ulink url="mailto:kuznet@ms2.inr.ac.ru">Alexey Kuznetsov 168<kuznet@ms2.inr.ac.ru></ulink>. 169It is now maintained by 170<ulink url="mailto:yoshfuji@skbuff.net">YOSHIFUJI Hideaki 171<yoshfuji@skbuff.net></ulink>. 172</para> 173</refsect1> 174 175 176<refsect1><title>SEE ALSO</title> 177<para> 178<citerefentry><refentrytitle/icmp/<manvolnum/7/</citerefentry>, 179<citerefentry><refentrytitle/inet/<manvolnum/7/</citerefentry>, 180<link linkend="ping"> 181<citerefentry><refentrytitle/ping/<manvolnum/8/</citerefentry></link>. 182</para> 183</refsect1> 184 185<refsect1><title>REFERENCES</title> 186<para> 187Deering, S.E.,ed "ICMP Router Discovery Messages", 188<ulink url="http://tools.ietf.org/rfc/rfc1256.txt"> 189RFC1256</ulink>, Network Information Center, SRI International, 190Menlo Park, Calif., September 1991. 191</para> 192</refsect1> 193 194<refsect1><title>SECURITY</title> 195<para> 196<command/rdisc/ requires <constant/CAP_NET_RAW/ to listen 197and send ICMP messages and capability <constant/CAP_NET_ADMIN/ 198to update routing tables. 199</para> 200</refsect1> 201 202<refsect1><title>AVAILABILITY</title> 203<para> 204<command/rdisc/ is part of <filename/iputils/ package 205and the latest versions are available in source form at 206<ulink url="http://www.skbuff.net/iputils/iputils-current.tar.bz2"> 207http://www.skbuff.net/iputils/iputils-current.tar.bz2</ulink>. 208</para> 209</refsect1> 210 211<![IGNORE[ 212<refsect1><title>COPYING</title> 213<para> 214<literallayout> 215Rdisc (this program) was developed by Sun Microsystems, Inc. and is 216provided for unrestricted use provided that this legend is included on 217all tape media and as a part of the software program in whole or part. 218Users may copy or modify Rdisc without charge, and they may freely 219distribute it. 220 221RDISC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE 222WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR 223PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE. 224 225Rdisc is provided with no support and without any obligation on the 226part of Sun Microsystems, Inc. to assist in its use, correction, 227modification or enhancement. 228 229SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE 230INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY RDISC 231OR ANY PART THEREOF. 232 233In no event will Sun Microsystems, Inc. be liable for any lost revenue 234or profits or other special, indirect and consequential damages, even if 235Sun has been advised of the possibility of such damages. 236 237Sun Microsystems, Inc. 2382550 Garcia Avenue 239Mountain View, California 94043 240</literallayout> 241</para> 242</refsect1> 243]]> 244 245 246</refentry> 247