??Filtering super-net static routes to be advertised to OSPF??

[Mariko]

]color blue]Please someone help me preventing super-net static routes from being advertised to Router B... Router A is running OSPF and BGP, and it has super-net static routes. Router B is running OSPF only. [/color]

Router A:

router ospf 1300
log-adjacency-changes
redistribute connected subnets
redistribute static subnets route-map static
redistribute bgp 63001 metric 100 metric-type 1 subnets

router bgp 63001
no bgp log-neighbor-changes
redistribute connected
redistribute static

ip route 0.0.0.0 0 128.0.0 202.122.20.1
ip route 128.0.0.0 128.0.0.0 202.122.20.1

Router B:

??? unable to see due to the security reason, but
it is running ospf...>:O>

I tried to use route-map,

access-list 20 permit ip 0.0.0.0 0 128.0.0
access-list 20 permit ip 128.0.0.0 128.0.0.0

route-map nonesupernet deny 10
match ip address 20

and applied it under ospf... and did not work.

I truly appreciate any ideas!!

 

[svermill]

This is not an appropriate use of route maps. Route maps are for policy-based routing. You "match" some condition and then "set" some value. Meeting the conditions for a "deny" statement simple means "route via normal (non-policy) channels." I think you will want to look into simple distribute lists to filter your routes.

 

[svermill]

I was half right. You can use a route-map for filtering redistribution. However, you have all of the statements backwards. You permit on the route-map and deny using the access list. This is because the route-map is checked first. So after it "passes" the route-map, it needs to be denied by the access list.

I still think that distribute lists are easier. But in researching a problem for someone else on another forum, I found that route-maps are the ONLY way to filter redistribution for IS-IS.

Who knew?

Good luck and let us know how that works.

Scott

 

[Mariko]

Svermill,

Thank you very much for your inputs!

I created a config with a distribute list, and
am planning to apply it under ospf.

I was also able to think of a way to "correctly"
filter routing update with route-map, using
null0 (is this right?). However, since I cannot
access the router that receives routing updates,
in other words, I have to use filtering that
can be applied to outbound packets, I cannot
use route-maps anyway....

Thank you very much

Mariko