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 (126.96.36.199) 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 (188.8.131.52) 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
Server side of router discovery protocol is supported by Cisco IOS
and by any more or less complete UNIX routing daemon, f.e gated. Or,
rdisc can act as responder, if compiled with -DRDISC_SERVER.
-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.
-r Responder mode, available only if compiled with
-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.
Set preference in advertisement. Available only with -r
Set maximum advertisement interval in seconds. Default is 600
secs. Available only with -r 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.
This program was developed by Sun Microsystems (see copyright notice
in source file). It was ported to Linux by Alexey Kuznetsov
<email@example.com>. It is now maintained by YOSHIFUJI Hideaki
This page is part of the iputils (IP utilities) project. Information
about the project can be found at ⟨http://www.skbuff.net/iputils/⟩.
If you have a bug report for this manual page, send it to
firstname.lastname@example.org, email@example.com. This page was obtained
from the project's upstream Git repository
⟨git://git.linux-ipv6.org/gitroot/iputils.git⟩ on 2017-03-13. If you
discover any rendering problems in this HTML version of the page, or
you believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a mail
iputils-151218 13 March 2017 RDISC(8)