irdd -- Internet Router Discovery daemon


/etc/irdd [ -b ] [ -d ]


irdd is an implementation of the Internet Router Discovery Protocol. This is a light-weight protocol implemented on top of icmp(ADMP).

The SCO TCP/IP start/stop script, tcp(ADMN), starts and stops the irdd daemon when a STARTDAEMONx/STOPDAEMONx variable pair is set to /etc/irdd in the tcp(SFF) configuration file (/etc/default/tcp).

On systems configured as a host, irdd generates several Router Solicitation messages when it first starts up. It then listens for Router Advertisement messages. Any routers that are detected are added as default routers using the precedence specified in the advertisement.

On systems configured as routers, irdd advertises the system periodically so that any hosts on the network running router discovery will be aware of the router. It also answers any solicitation requests received from newly initialized hosts.

The behavior of irdd can be tuned using its configuration file, /etc/irdd.conf. See irdd.conf(SFF) for information on the configuration file.

The flags are:

Specify the use of broadcast datagrams instead of multicast datagrams.

Turn on debugging.
irdd also implements support for multiple default routers and switching of routers when failure is detected.

If ICMP Router Discovery is not in use on the local network, multiple default routers can be statically configured in /etc/irdd.conf.

The kernel detects failure of next-hop routers on media using the ARP protocol or in cases where TCP traffic is flowing through the failed router. In this case, if an alternate router exists, irdd will install a new default router. Note that in non-redundant network topologies this may not help, and there will be no recourse other than to wait for the failed router to be repaired.

irdd rescans its configuration file periodically. Reconfiguration can also be forced by sending the irdd process a SIGHUP.


startup configuration file

irdd configuration file

See also

arp(ADMP), gated(ADMN), icmp(ADMP), irdd.conf(SFF), routed(ADMN), tcp(ADMP)

Standards conformance

irdd is conformant with RFC 1256
© 2005 The SCO Group, Inc. All rights reserved.
SCO OpenServer Release 6.0.0 -- 02 June 2005