Configuring a non-routing host

After you configure one or more routers between the local network and other networks, you must configure the routing tables of the hosts on the local network so that they can send packets to those networks. This is done using the route command or a routing daemon, usually routed.

The non-routing host uses the information you supply in the route command to build or update its internal routing table. Alternatively, it can use a routing daemon to create a routing table based on broadcasts received from the router(s). The host uses the table to find the appropriate router (``next hop'') to the destination to which it is trying to send packets.

Either the route command or a routing daemon such as routed must be run on the client every time TCP/IP is started. You must modify the client's Internet services configuration file, /etc/inet/config to ensure that either the command or the daemon is run automatically after booting (see config_inet(4tcp)). You can edit the configuration file to specify different kinds of routing behavior, as described below:

• If there is only one router on the local network, you can set up the config file so that, by default, attempts by your client to reach outside the local network are directed to this router. Since there is only one router to access external networks, no additional processing is needed on the client. See ``Specifying a default router'' for details.

• If your client has more than one router available to it on the local network, you can direct traffic to specific networks through specific routers. See ``Specifying routers'' for details.

• By preference, you should run a routing daemon such as routed or gated on a non-routing host if the local network has more than one router to other networks. It is possible to define a default route to one of the routers and let ICMP ``redirect messages'' update the host's routing table, but this will fail if the default router becomes unavailable. If the host is connected to a router that runs an active routing daemon, the host can take advantage of the router's dynamic routing tables by running routed in passive mode.

  See ``Running a routing daemon on a non-routing host'' for details.

  It is also possible to configure a non-routing host to find a suitable default router dynamically using the Internet router discovery (IRD) protocol. Both routed and gated support IRD.