Networking Guide
Chapter 5, Configuring Internet Protocol (IP) routing

routed description

routed description

The routed daemon implements version I of the Routing Information Protocol (RIP I) to exchange routing information. It uses the /etc/gateways file to initialize static routes to distant networks. The /etc/gateways file is described in the reference manual page routed(ADMN).

If you wish to run routed, ensure that the file /etc/gated.conf does not exist. If it does, you must remove it, move it to another directory, or rename it. Otherwise, the gated daemon will execute instead of routed the next time your host reboots.

When routed starts, it reads the /etc/gateways file (if it exists) and installs the routes defined there into its routing table. It then broadcasts on each local network to find other hosts running routed. If such hosts exist, the routing daemons cooperate in maintaining a globally consistent view of routing within an autonomous system (AS). This view can be extended to include remote networks also running routed by setting up suitable entries in /etc/gateways.

Another approach to routing to nonlocal networks using routed is to define a default or wildcard route to a smart gateway. This gateway would then ICMP routing-redirect information dynamically create a routing database. This is done by adding an entry to /etc/tcp that invokes the route(ADMN) command, as in the following example:

   /etc/route add default smart-gateway
The route command is used to manually manipulate routing tables. See the route(ADMN) manual page for more information.

The host uses the default route to the smart gateway as a last resort in routing packets to their destinations. Assuming the smart gateway will generate ICMP routing-redirect messages, the host will update its routing table entries based on the redirect messages received from the smart gateway.

This approach has certain advantages over using the routed daemon, but it is unsuitable in an environment where there are only bridges (for example, bridges do not generate ICMP routing-redirect messages). Further, if the smart gateway goes down, there is no way to maintain service except to alter the routing table manually using the route command.

The host always listens to, and processes, ICMP routing-redirect messages, and so it is possible to combine both of the above facilities. For example, the routed daemon might be used to maintain up-to-date information about routes to local networks, while employing the default routing techniques for distant networks.