RIP isn't exactly the most complex routing protocol on the CCNA exam, but that makes it easy to overlook some of the important details you must keep in mind in order to pass the exam! To help you review for the exam, here are just a few of those details!

RIPs default behavior is to send version 1 updates, but to accept both version 1 and 2 routing updates.

R2(config)#router rip

R2(config-router)#net 172.16.0.0

R2(config-router)#^Z

R2#show ip protocols

Routing Protocol is "rip"

Sending updates every 30 seconds, next due in 6 seconds

Invalid after 180 seconds, hold down 180, flushed after 240

Outgoing update filter list for all interfaces is

Incoming update filter list for all interfaces is

Redistributing: rip

Default version control: send version 1, receive any version

Interface Send Recv Key-chain

Serial0 1 1 2

By default, RIP v2 autosummarizes routing updates sent across classful network boundaries. To disable this behavior, run no auto-summary under the RIP process.

R1#conf t

R1(config)#router rip

R1(config-router)#version 2

R1(config-router)#no auto-summary

You do not specify a subnet mask or wildcard mask when configuring RIP just the classful network, even if youre running RIP v2.

R1#conf t

Enter configuration commands, one per line. End with CNTL/Z.

R1(config)#router rip

R1(config-router)#version 2

R1(config-router)#no auto-summary

R1(config-router)#network 172.10.0.0 ?

Debug ip rip displays the routing updates and metrics as the advertisements are sent and requested. To see this in action without waiting for the next regularly scheduled update, run clear ip route *.

R1#debug ip rip

RIP protocol debugging is on

R1#clear ip route *

01:16:54: RIP: sending v1 update to 255.255.255.255 via Loopback1 (1.1.1.1)

01:16:54: network 2.0.0.0, metric 2

01:16:54: network 3.0.0.0, metric 2

01:16:54: network 172.16.0.0, metric 1

01:16:54: network 10.0.0.0, metric 2

01:16:54: RIP: sending v1 update to 255.255.255.255 via Serial0 (172.16.123.1)

01:16:54: subnet 172.16.123.0, metric 1

01:16:54: network 1.0.0.0, metric 1

01:16:54: network 2.0.0.0, metric 2

01:16:54: network 3.0.0.0, metric 2

01:16:54: network 10.0.0.0, metric 2

To see only the routes discovered by a routing protocol, run show ip route followed by the name of the protocol:

R1#show ip route rip

R 2.0.0.0/8 [120/1] via 172.16.123.2, 00:00:26, Serial0

R 3.0.0.0/8 [120/1] via 172.16.13.2, 00:00:09, Serial1

[120/1] via 172.16.123.3, 00:00:09, Serial0

R 10.0.0.0/8 [120/1] via 172.16.13.2, 00:00:09, Serial1

[120/1] via 172.16.123.3, 00:00:09, Serial0

[120/1] via 172.16.123.2, 00:00:26, Serial0

And don't forget - to turn off all currently running debugs, run undebug all.

R1#undebug all

All possible debugging has been turned off

Don't overlook RIP and IGRP when it comes to the CCNA exam. OSPF and EIGRP are more complex to configure, but you need to understand how distance vector protocols work in order to pass the CCNA!