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Passive-Interfaces

Routing Gurus!

Can an router running ospf/eigrp establish adjacency/neighbor status with a neighbor router connected via a passive-interface? If so, how?

Thanks.

1 ACCEPTED SOLUTION

Accepted Solutions

Re: Passive-Interfaces

Hi, here is the answer for your ospf/eigrp and passive interface question.

http://www.cisco.com/warp/public/103/16.html

hope this helps

Rgds

Jorge

3 REPLIES

Re: Passive-Interfaces

Hi, here is the answer for your ospf/eigrp and passive interface question.

http://www.cisco.com/warp/public/103/16.html

hope this helps

Rgds

Jorge

New Member

Re: Passive-Interfaces

Jorge,

Thanks... I inferred from the document that a router running ospf with a passive interface can still establish a neighbor adj on that interface.

If this is not correct let me know.

Re: Passive-Interfaces

Hi,

No, in OSPF the passive interface will not form adjacency because is not participating in routing, therefore OSPF will not count that interface in its routing computation.

Also, remember, adjacent/neighbors have a direct connected interface.

Before OSPF adjacency is formed, it must go through several Startup/states changes before it becomes fully adjacent with its neighbor in a FULL State manner to ultimately participate in OSPF routing calculations.

You can lookup OSPF startup states to learn about how OSPF stablish adjacency.

Hope this helped

Rgds

Jorge

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