Automatic Routing Protocol Selection

The startup script then must determine whether to start up a routing protocol (RIP or RDISC) on the machine or use static routing.

To Select Static Routing on a Host

If the host is a diskless client or network client, add an entry for a router on the network into /etc/defaultrouter. (See "/etc/defaultrouter File".) A single static default route is then installed in the routing table. Under this condition, the host does not run any dynamic routing protocol (such as RIP and RDISC).

To Select Dynamic Routing on a Host

To force a diskless client or network client to select a dynamic routing protocol, its /etc/defaultrouter file should be empty. The type of dynamic routing used is selected according to the following criteria:

• 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.

• If the network router is not running RDISC or fails to respond to the RDISC queries, then in.rdisc on the host exits. The host then starts in.routed, which runs RIP.