— Interface command: ip rip authentication mode md5
— Interface command: no ip rip authentication mode md5

Set the interface with RIPv2 MD5 authentication.

— Interface command: ip rip authentication mode text
— Interface command: no ip rip authentication mode text

Set the interface with RIPv2 simple password authentication.

— Interface command: ip rip authentication string string
— Interface command: no ip rip authentication string string

RIP version 2 has simple text authentication. This command sets authentication string. The string must be shorter than 16 characters.

— Interface command: ip rip authentication key-chain key-chain
— Interface command: no ip rip authentication key-chain key-chain

Specifiy Keyed MD5 chain.

     !
     key chain test
      key 1
       key-string test
     !
     interface eth1
      ip rip authentication mode md5
      ip rip authentication key-chain test
     !