Configuring Dynamic Routing

Access RIP configuration mode

router rip
  • Prompt will show up as Router(config-router)#
  • When enabling RIP, the default version is RIPv1.
  • To disable and eliminate RIP, use the no router rip global configuration command. This command stops the RIP process and erases all existing RIP configurations.
  • Upon enabling, need to advertise networks with network <network-address>

Enable and Verify RIPv2

By default, when a RIP process is configured on a Cisco router, it is running RIPv1, as shown in Figure 1. However, even though the router only sends RIPv1 messages, it can interpret both RIPv1 and RIPv2 messages. A RIPv1 router ignores the RIPv2 fields in the route entry.

Use the version 2 router configuration mode command to enable RIPv2, as shown in Figure 2. Notice how the show ip protocols command verifies that R2 is now configured to send and receive version 2 messages only. The RIP process now includes the subnet mask in all updates, making RIPv2 a classless routing protocol.

Note: Configuring version 1 enables RIPv1 only, while configuring no version returns the router to the default setting of sending version 1 updates but listening for version 1 and version 2 updates.

Propogate a Default Route

The default-information originate router configuration command. This instructs R1 to originate default information, by propagating the static default route in RIP updates.

RIP Routing Configuration Mode Commands

network <network-address>       # Enables RIP on all interfaces on that network.
version 2                       # Enables RIPv2
version 1                       # Enables RIPv1 only
no version                      # Returns to default setting: send v1, listen v1+v2
no auto-summary                 # Disables default automatic summarization (RIPv2)

passive-interface <interface>   # Prevent transmission of routing updates out interface
                                # However, still allows network to be advertised
passive-interface g0/0
passive-interface default       # Makes all interfaces passive
no passive-interface <intf>     # Re-enables passive transmission of routing updates

Verify RIP Routing

show ip protocols
show ip route

Propogate a Default Route

To propagate a default route in RIP, the edge router must be configured with a default static route using the ip route 0.0.0.0 0.0.0.0 command:

ip route 0.0.0.0 0.0.0.0 <exit-interface> <next-hop IP>

Next configure router to propogate the static default route in RIP updates:

router rip
default-information originate