By entering the RIP router configuration mode, the router is instructed to run RIP. But the router still needs to know which local interfaces it should use for communication with other routers, as well as which locally connected networks it should advertise to those routers.

To enable RIP routing for a network, use the network network-address router configuration mode command. Enter the classful network address for each directly connected network. This command:

Note: If a subnet address is entered, the IOS automatically converts it to the classful network address. Remember RIPv1 is a classful routing protocol for IPv4. For example, entering the network command would automatically be converted to network in the running configuration file. The IOS does not give an error message, but instead corrects the input and enters the classful network address.

In Figure 1, the network command is used to advertise the R1 directly connected networks.

Use the Syntax Checker in Figure 2 to configure a similar configuration on R2 and R3.