denying ping on router

[carl_townshend]

I was setting up my routers the other day, which are running ospf, I did an access list that denied any icmp trafic from its neighbour router, This causeed ospf to drop this rouyter is that correct ? does it use icmp for its hello ?

[gwhuang5398]

OSPF doesn't use ICMP for its Hello packets. What's the access list you configured? If you can post the config.

Gary

[carl_townshend]

What protocol does it use for Hellos then ? I think the below port is corrent, It was basically blockinh anything !!

[Harold Ritter]

Carl,

OSPF is transported directly over IP and has its own protocol number, which is 89.

Hope this helps. Please rate if it does.

[Harold Ritter]

By the way, here's where you can find a list of assigned protocol numbers:

http://www.iana.org/assignments/protocol-numbers

Hope this helps,

[Harold Ritter]

Carl,

Did you specify an explicit "permit ip any any" at the end of the ACL? Remember that there is always an implicit "deny ip any any" at the end of any ACL. That is probably why your ospf adjacency went down.

Hope this helps,