rdisc(8) [redhat man page]
RDISC(8) System Manager's Manual: iputils RDISC(8) NAME
rdisc - network router discovery daemon SYNOPSIS
rdisc [ -abdfstvV] [ send_address] [ receive_address] DESCRIPTION
rdisc implements client side of the ICMP router discover protocol. rdisc is invoked at boot time to populate the network routing tables with default routes. rdisc listens on the ALL_HOSTS (224.0.0.1) multicast address (or receive_address provided it is given) for ROUTER_ADVERTISE messages from routers. The received messages are handled by first ignoring those listed router addresses with which the host does not share a network. Among the remaining addresses the ones with the highest preference are selected as default routers and a default route is entered in the kernel routing table for each one of them. Optionally, rdisc can avoid waiting for routers to announce themselves by sending out a few ROUTER_SOLICITATION messages to the ALL_ROUTERS (224.0.0.2) multicast address (or send_address provided it is given) when it is started. A timer is associated with each router address and the address will no longer be considered for inclusion in the the routing tables if the timer expires before a new advertise message is received from the router. The address will also be excluded from consideration if the host receives an advertise message with the preference being maximally negative. Server side of router discovery protocol is supported by Cisco IOS and by any more or less complete UNIX routing daemon, f.e gated. OPTIONS
-a Accept all routers independently of the preference they have in their advertise messages. Normally rdisc only accepts (and enters in the kernel routing tables) the router or routers with the highest preference. -b Opposite to -a, i.e. install only router with the best preference value. It is default behaviour. -d Send debugging messages to syslog. -f Run rdisc forever even if no routers are found. Normally rdisc gives up if it has not received any advertise message after after soliciting three times, in which case it exits with a non-zero exit code. If -f is not specified in the first form then -s must be specified. -s Send three solicitation messages initially to quickly discover the routers when the system is booted. When -s is specified rdisc exits with a non-zero exit code if it can not find any routers. This can be overridden with the -f option. -t Test mode. Do not go to background. -v Be verbose i.e. send lots of debugging messages to syslog. -V Print version and exit. HISTORY
This program was developed by Sun Microsystems (see copyright notice in source file). It was ported to Linux by Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>. SEE ALSO
icmp(7), inet(7), ping(8). REFERENCES
Deering, S.E.,ed "ICMP Router Discovery Messages", RFC1256, Network Information Center, SRI International, Menlo Park, Calif., September 1991. SECURITY
rdisc requires CAP_NET_RAWIO to listen and send ICMP messages and capability CAP_NET_ADMIN to update routing tables. AVAILABILITY
rdisc is part of iputils package and the latest versions are available in source form for anonymous ftp ftp://ftp.inr.ac.ru/ip-rout- ing/iputils-current.tar.gz. iputils-020927 27 September 2002 RDISC(8)
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in.rdisc(1M) System Administration Commands in.rdisc(1M) NAME
in.rdisc, rdisc - network router discovery daemon SYNOPSIS
/usr/sbin/in.rdisc [-a] [-f] [-s] [send-address] [receive-address] /usr/sbin/in.rdisc -r [-p preference] [-T interval] [send-address] [receive-address] DESCRIPTION
in.rdisc remains part of the software distribution of the Solaris Operating Environment. It is, however, not used by default. in.routed(1M) includes the functionality provided by in.rdisc. See routeadm(1M) for details of how to specify the IPV4 routing daemon. in.rdisc implements the ICMP router discovery protocol. The first form of the command is used on hosts and the second form is used on routers. in.rdisc can be invoked in either the first form (host mode) or second form (router mode). On a host, in.rdisc populates the network routing tables with default routes. On a router, advertises the router to all the hosts. Host (First Form) On a host, in.rdisc listens on the ALL_HOSTS (224.0.0.1) multicast address for ROUTER_ADVERTISE messages from routers. The received mes- sages are handled by first ignoring those listed router addresses with which the host does not share a network. Among the remaining addresses, the ones with the highest preference are selected as default routers and a default route is entered in the kernel routing table for each one of them. Optionally, in.rdisc can avoid waiting for routers to announce themselves by sending out a few ROUTER_SOLICITATION messages to the ALL_ROUTERS (224.0.0.2) multicast address when it is started. A timer is associated with each router address. The address will no longer be considered for inclusion in the routing tables if the timer expires before a new advertise message is received from the router. The address will also be excluded from consideration if the host receives an advertise message with the preference being maximally negative or with a lifetime of zero. Router (Second Form) When in.rdisc is started on a router, it uses the SIOCGIFCONF ioctl(2) to find the interfaces configured into the system and it starts lis- tening on the ALL_ROUTERS multicast address on all the interfaces that support multicast. It sends out advertise messages to the ALL_HOSTS multicast address advertising all its IP addresses. A few initial advertise messages are sent out during the first 30 seconds and after that it will transmit advertise messages approximately every 600 seconds. When in.rdisc receives a solicitation message, it sends an advertise message to the host that sent the solicitation message. When in.rdisc is terminated by a signal, it sends out an advertise message with the preference being maximally negative. OPTIONS
-a Accept all routers independent of the preference they have in their advertise messages. Normally, in.rdisc only accepts (and enters in the kernel routing tables) the router or routers with the highest preference. -f Run in.rdisc forever even if no routers are found. Normally, in.rdisc gives up if it has not received any advertise message after soliciting three times, in which case it exits with a non-zero exit code. If -f is not specified in the first form then -s must be specified. -r Act as a router, rather than a host. -s Send three solicitation messages initially to quickly discover the routers when the system is booted. When -s is specified, in.rdisc exits with a non-zero exit code if it can not find any routers. This can be overridden with the -f option. -p preference Set the preference transmitted in the solicitation messages. The default is zero. -T interval Set the interval between transmitting the advertise messages. The default time is 600 seconds. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWroute | +-----------------------------+-----------------------------+ SEE ALSO
in.routed(1M), routeadm(1M), ioctl(2), gateways(4), attributes(5), icmp(7P), inet(7P) Deering, S.E., editor, ICMP Router Discovery Messages, RFC 1256, Network Information Center, SRI International, Menlo Park, California, September 1991. SunOS 5.10 5 Nov 2004 in.rdisc(1M)