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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | HISTORY | SEE ALSO | REFERENCES | SECURITY | AVAILABILITY | COLOPHON |
RDISC(8) iputils RDISC(8)
rdisc - network router discovery daemon
rdisc [-abdfrstvV] [-p preference] [-T max_interval] [send_address]
[receive_address]
rdisc implements client side of the ICMP Internet Router Discovery
Protocol (IRDP). 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 if it is provided) 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 if it is
provided) when it is started.
A timer is associated with each router address and 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
received advertise message has a preference of maximum negative.
Server side of router discovery protocol is supported by Cisco IOS
and by any more or less complete UNIX routing daemon, for example
gated. If compiled with ENABLE_RDISC_SERVER, rdisc can act as
responder.
-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. This is the default behaviour.
-d
Send debugging messages to syslog.
-f
Keep rdisc running in the background even if no routers are
found. Normally rdisc gives up if it has not received any
advertise message after soliciting three times. In this 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
ENABLE_RDISC_SERVER.
-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.
-p preference
Set preference in advertisement messages. Available only with -r
option.
-T max_interval
Set maximum advertisement interval in seconds. Default is 600.
Available only with -r option.
-t
Test mode. Do not go to background.
-v
Be verbose and 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
<kuznet@ms2.inr.ac.ru>.
icmp(7), inet(7), ping(8).
RFC1256 ICMP Router Discovery Messages. S. Deering, Ed.. September
1991.
rdisc requires CAP_NET_RAW to listen and send ICMP messages and
capability CAP_NET_ADMIN to update routing tables.
rdisc is part of iputils package.
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
yoshfuji@skbuff.net, netdev@vger.kernel.org. This page was obtained
from the project's upstream Git repository
⟨https://github.com/iputils/iputils.git⟩ on 2020-08-13. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2020-08-10.) 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 to man-pages@man7.org
iputils s20190709 RDISC(8)
Pages that refer to this page: icmp(7)