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OSPF route filtering

mylest
Level 1
Level 1

Can anyone please tell me how I can stop static routes from being redistributed to one router but continue to be redistributed to another? All router are in the same OSPF autonomous system 1:

Please see router output below:

----------------------------------------------------------

ROUTER B:

----------------------------------------------------------

router ospf 1

log-adjacency-changes

redistribute static subnets

network 172.22.127.100 0.0.0.3 area 0

network 172.22.11.0 0.0.0.255 area 3

----------------------------------------------------------

I am redistributing my static routes into OSPF. I want ROUTER A to receive the statics, but don't want ROUTER C to receive the statics. Any suggestions?

Thanks

2 Replies 2

thisisshanky
Level 11
Level 11

OSPF has the behaviour of sending routes as LSAs and not copies of routing table. So if you put a output filter to filter routes in router B, you will still see the LSAs in A and C, and routes wont get filtered. SO you might want to put a input filter list at C to filter routes from coming into the routing table of C. Still you will see the LSA in the database of C.

configure a distribute-list in C

router ospf 10

distribute-list 10 in

acces-list 10 permit

permit those networks you want to see, the rest will be denied and wont be in the routing table.

Hope it helps

Sankar Nair
UC Solutions Architect
Pacific Northwest | CDW
CCIE Collaboration #17135 Emeritus

Funny this should come up, I was just talking with someone about this is morning.

From Cisco: "OSPF routes can't be filtered from entering the OSPF database. The distribute-list in command only filters routes from entering the routing table, but it doesn't prevent link-state packets from being propagated.

The command distribute-list out works only on the routes being redistributed by the autonomous system boundary routers (ASBRs) into OSPF. It can be applied to external type 2 and external type 1 routes, but not to intra-area and inter-area routes."

Steve

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