OSPF LSA Type 5 Filtering on Cisco IOS

Hello Billing

If we applied this route map as you have it here, the following would happen:

You have an access list that denies host 172.16.1.1 and permits everything else. This means that this access list, within a route map will match EVERYTHING except for that specific IP.

When you add it to the route map, with a permit statement, then every time a packet with an IP address other than 172.16.1.1, it will be permitted. Because of the implicit deny at the end of the route map, everything else, which is essentially 172.16.1.1 alone, will be denied.

So a match (which takes place with everything except 172.16.1.1) in your case will permit redistribution. A lack of matching (which will only occur with 172.16.1.1) will result in a denial of redistribution.

So yes, your solution would work. It may be considered a little bit counterintuitive, but if the thought process works for you then so be it!

I hope this has been helpful!

Laz

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