rip authentication...

same same... except change to ver 2...

on r5 and r6 add

key chain suck-key
key 1
key-string suck- key

and on the applicable interfaces

ip rip authentication key-chain suck-key

r6#sh key chain
Key-chain suck-key:
    key 1 -- text "suck- key"
        accept lifetime (always valid) - (always valid) [valid now]
        send lifetime (always valid) - (always valid) [valid now]

*Sep  3 16:50:46: RIP: received packet with text authentication suck- key
*Sep  3 16:50:46: RIP: received v2 update from 172.16.2.2 on FastEthernet0/1
*Sep  3 16:50:46:      1.0.0.0/8 via 0.0.0.0 in 1 hops
*Sep  3 16:50:46:      10.0.0.0/8 via 0.0.0.0 in 1 hops
*Sep  3 16:50:46:      192.168.1.0/24 via 0.0.0.0 in 1 hops
*Sep  3 16:50:46:      192.168.2.0/24 via 0.0.0.0 in 1 hops

set both sides to md5 authentication...

ip rip authenti mode md5

r6#
*Sep  3 16:54:58: RIP: received packet with MD5 authentication

that was very refreshing...