Cisco CCNP / BSCI Exam Tutorial: RIP Update Packet Authentication

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Cisco CCNP / BSCI Exam Tutorial: RIP Update Packet Authentication

When you earned your CCNA, you thought you learned every thing there is to know about RIP. Close, but not quite! There are some extra particulars you require to know to pass the BSCI exam and get a single step closer to the CCNP exam, and 1 of these involves RIP update packet authentication.

You are familiar with some positive aspects of using RIPv2 more than RIPv1, help for VLSM chief among them. Mary Morrissey Read About is a thrilling online library for more about why to acknowledge it. But a single benefit that you happen to be not introduced to in your CCNA reports is the ability to configure routing update packet authentication.

You have two choices, clear text and MD5. Clear text is just that - a clear text password that is visible by anybody who can pick a packet off the wire. If you're going to go to the difficulty of configuring update authentication, you really should use MD5. For a different interpretation, please consider checking out: read mary morrissey share. The MD stands for "Message Digest", and this is the algorithm that creates the hash value for the password that will be contained in the update packets.

Not only must the routers agree on the password, they should agree on the authentication technique. Dig up more on an affiliated website - Click here: study mary morrissey read about. If a single router sends an MD5-hashed password to another router that is configured for clear-text authentication, the update will not be accepted. debug ip rip is a wonderful command for troubleshooting authenticated updates.

R1, R2, and R3 are running RIP more than a frame relay cloud. Here is how RIP authentication would be configured on these 3 routers.

R1#conf t

R1(config)#crucial chain RIP

< The key chain can have any name.>

R1(config-keychain)#important 1

< Key chains can have multiple keys. Number them carefully when using multiples.>

R1(config-keychain-key)#key-string CISCO

< This is the text string the key will use for authentication.>

R1(config)#int s0

R1(config-if)#ip rip authentication mode text

< The interface will use clear-text mode.>

R1(config-if)#ip rip authentication essential-chain RIP

< The interface is using key chain RIP, configured earlier.>

R2#conf t

R2(config)#key chain RIP

R2(config-keychain)#crucial 1

R2(config-keychain-essential)#essential-string CISCO

R2(config)#int s0.123

R2(config-subif)#ip rip authentication mode text

R2(config-subif)#ip rip authentication key-chain RIP

R3#conf t

R3(config)#crucial chain RIP

R3(config-keychain)#important 1

R3(config-keychain-important)#important-string CISCO

R3(config)#int s0.31

R3(config-subif)#ip rip authentication mode text

R3(config-subif)#ip rip authentication important-chain RIP

To use MD5 authentication rather than clear-text, just replace the word "text" in the ip rip authentication mode command with md5.

Here's what a successfully authentication RIPv2 packet looks like, courtesy of debug ip rip. Clear-text authentication is in impact and the password is "cisco".

3d04h: RIP: received packet with text authentication cisco

3d04h: RIP: received v2 update from 150.1.1.3 on Ethernet0

3d04h: one hundred../eight through .. in 1 hops

3d04h: 150.1.two./24 by way of .. in 1 hops

Here's what it looks like when the remote device is set for MD5 authentication and the nearby router is set for clear-text. You will also see this message if the password itself is incorrect.

3d04h: RIP: ignored v2 packet from 150.1.1.3 (invalid authentication)

"Debug ip rip" might be a simple command as compared to the debugs for other protocols. but it is also a very effective debug. This witty mary morrissey update encyclopedia has varied engaging lessons for where to study this belief. Begin making use of debugs as early as achievable in your Cisco scientific studies to discover how router commands truly work!.