TCP/IP and Data Communications Administration Guide

Turning Off ICMP Router Discovery on the Router

If the automatic selection of RIP rather than RDISC by a host is to work reliably, the routers in the network (particularly those running RDISC) must also work reliably.

If your routers are not running RDISC and you install a single Solaris router, by default all hosts connected to that router rely on it alone. To have the hosts on that network use the other routers as well, turn off RDISC on the new router. To do this, change the name of the router's /usr/bin/in.rdisc file to some other file name and reboot the router.