Passive Interface
The passive-interface command prevents routing updates from being sent out
an interface that runs the routing protocol. RIP and IGRP do not send updates
out an interface. It prevents other routing protocols from sending hellos out of
an interface; thus, they don’t discover neighbors or form an adjacency out that
interface. To disable the protocol on one interface, use the command passiveinterface
interface. To turn off the protocol on all interfaces, use passiveinterface
default. You can then use no passive-interface interface for the
ones that should run the protocol, as shown:
Router(config)#router eigrp 7
Router(config-router)#passive-interface default
Router(config-router)#no passive-interface s0/0/0