Passive-Interfaces

[gbryant]

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.

[JORGE RODRIGUEZ · Accepted solution]

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

[gbryant]

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.

[JORGE RODRIGUEZ]

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