passive-interface type number
no passive-interface type number
type Interface type number Interface number default Sets all interfaces as passive. Individual interfaces can have the passive parameter removed by using the no passive-interface type number command. This parameter is useful in ISPs and large enterprise networks that have routers that contain more than 200 interfaces.
The passive-interface command keeps a router from sending routing updates out an interface.
Misconceptions:Router(config-router)#passive interface serial 0/0
A passive interface performs differently when using EIGRP, OSPF, IS-IS, and BGP than it does with RIP and IGRP. When using the passive-interface command with EIGRP, inbound and outbound hellos are prevented. Therefore, EIGRP neighboring cannot occur. Use the distribute-list command with EIGRP to control routing updates. When using the passive-interface command with OSPF, routing information is neither sent, nor received through the specified interface. The best way to control OSPF routing updates is to create a stub, NSSA, or totally stub area. The distribute-list command can also be used, but see the Misconceptions area of that command for information on using it within OSPF. The passive-interface command does not work with BGP. BGP is not a traditional routing protocol in that it is never really run on an interface. Instead a neighbor (peer) is specified. BGP has no idea which physical interface is actually performing the neighbor peering. If two BGP neighbors are NOT to peer with each other, do not enter neighbor statements. When configuring other routing protocols, an interface is never specified. Instead the network command is used. When the protocol is active, the protocol knows that an interface is active for that particular protocol. This can been seen by using the show ip protocols command. Conversely, with BGP, network commands are used to specify what networks to advertise and neighbor commands to specify BGP peers. With BGP, use a route map to filter out routes.
� Cisco Systems, Inc. 2001, 2002, 2003
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