Cisco CCNA Certification Exam Training Tutorial:

RIP Test Prep Tips

By Chris Bryant, CCIE #12933

In your CCNA exam studies, it's easy to overlook RIP in the big scheme of things. OSPF has many more details, as does EIGRP - but RIP has some details you must know in order to pass the Cisco CCNA exam. RIP is also a very popular network routing protocol, so you need to know about this important protocol for use in real-world networks as well! Here are eight CCNA exam tips to help you in your test prep!

CCNA Test Prep Tip #1: RIP's default behavior is to send version 1 updates only, but to accept both versions 1 and 2.

To be frank, this is a strange little default, but to be even more frank, you better know this! The all-purpose command show ip protocols bears this out:

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

CCNA Test Prep Tip #2: One RIP version 2 default behavior is to autosummarize routes advertised across classful boundaries. To disable this behavior, run the no auto-summary command under the RIP process.

CCNA Test Prep Tip #3: To hardcode RIP to send and receive only version 1 or version 2, run the appropriate version command under the RIP process. An example of both of these tips is shown below.

R1#conf t
R1(config)#router rip
R1(config-router)#version 2
R1(config-router)#no auto-summary

CCNA Test Prep Tip #4: RIP version 2 supports variable-length subnet masking (VLSM), but you still enter the classful network number under the RIP process.

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

CCNA Test Prep Tip #5: To see the routes being advertised in RIP updates and the metrics of these routes, run debug ip rip.

CCNA Test Prep Tip #6: To see these updates immediately after turning the debug on, run clear ip route * to clear the routing table of its dynamic routes.

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

CCNA Test Prep Tip #7: If you want to see only a certain kind of route from the entire routing table, run show ip route followed by the protocol or route type (static, for example).

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

CCNA Test Prep Tip #8: Don't forget to turn your debugs off when you're done! To turn all debugs off at once, run undebug all. To turn off individual debugs, run the command no debug followed by the type of debug you want to turn off - no debug ip rip, for example.

R1#undebug all
All possible debugging has been turned off

To your success,

Chris Bryant

CCIE #12933

chris@thebryantadvantage.com