Become superuser on the host.
Ensure that the /etc/defaultrouter file is empty.
If this file is empty, a network client is forced to select a dynamic routing protocol.
If the /usr/sbin/in.rdisc program exists, the startup script starts in.rdisc. Any router on the network that is running RDISC then responds to any RDISC queries from the host. If at least one router responds, the host selects RDISC as its routing protocol.