Using Prefix-List for marching only one IP address

[rezaalikhani]

Hi all;

Suppose I receive routes with "10.149.42.0/24" prefix from adjacent router and I want to match exactly the "10.149.42.254" IP address, for filtering purpose. How can I match exactly this IP address using a prefix list?

Thanks

[Richard Burts]

Can you clarify what kind of filtering purpose you are asking about? Is it filtering routing information about that host address or is it filtering traffic to or from that host address?

[rezaalikhani]

I want to use

 distribute-list

in OSPF to filter 10.149.42.254 address, so preventing it to insert in the routing table.

[Jon Marshall]

Are you receiving a route advertisement for that specific IP ? 

It sounds from your description as you are only receiving the /24 so you can't then stop a specific IP from that range being inserted in the routing table. 

Can you clarify ?

Jon

[MHM Cisco World]

can you more elaborate ?

anyway this link for OSPF route filter 

http://www.ccieordie.com/2-3-g-ospf-filtering

[paul driver · Accepted solution]

Hello

Note:- The example below will ONLY filter from that router and NOT the ospf D?B

Example:

ip prefix-list HOST deny 10.149.42.254/32
ip prefix-list HOST permit 0.0.0.0/0 le 32


router ospf x
distribute-list prefix HOST  in