RIP Updates

A number of times I've come across these questions in workbooks.

- RIP shouldn't broadcast updates but directed updates to a specific neighbor.
When we use "neighbor x.x.x.x" command under router RIP process, it send unicast updates to the neighbor alongwith broadcast. To allow RIP to only send directed updates to a neighbor, use passive-interface command alongwith neighbor command.

- RIP updates shouldn't be received by interfaces participating in other routing protocols.
Though putting an interface in passive mode stops it from sending updates but doesnt stop it from recieving updates. So theres a chance that RIP broadcast may be received by the interfaces participating in other routing protocols. To avoid updates, either use the neighbor command under rip process to choose which neighbor should recieve updates. or use an acl that blocks rip communication.
access-list 100 deny udp any eq rip any eq rip
access-list 100 permit ip any any