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New Member

OSPF

Hi

We got 2 routers routerA and routerB running OSPF as routing protocol. what we want is routerA to send all the routing tables to routerB but we dont want routerB to send updates or limited updates to routerA. can someone tell me that is it possbile, if yes can you help me.

Thanks

5 REPLIES

Re: OSPF

Sure, just use route-maps to allow or deny whatever routing updates you want...

Here's a good link...

http://www.cisco.com/en/US/customer/products/sw/iosswrel/ps1829/products_feature_guide09186a008012db77.html

Gold

Re: OSPF

Distribute lists and route maps will only block routes from being placed in the routing table of the local router, they won't prevent the routes from being readvertises to an adjacenct neighbor, for instance.

There are only a couple of ways to block routes between two routers, and both of them require B to be an ABR. The first is what Herald mentioned, making B an ABR, and A part of a totally stubby area. The other would be to make B an ABR, and use type 3 filtering to block the routes being sent to A (this would work whether A is part of area 0 or some other area outside te backbone).

http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_feature_guide09186a00800b5d4f.html

You could also, using this feature, make A an ABR and filter the routes inbound, as long as they are type 3's (which isn't likely). If the routes are externals, you can still use the stubby area trick, or you can make B an ABR, summarize the routes, then block the summaries with the type 3 filtering above.

Hope that helps...

:-)

Russ.W

New Member

Re: OSPF

There are 2 other ways that you could accomplish this with out having to change your ospf network type. You could use the command "ip ospf database-filter all out" under the interface on Router B to filter all LSA's from being sent out that interface, or you could use the command "neighbor x.x.x.x database-filter all out" under the ospf config of router B to just filter out LSA's to thatspecific neighbor

Cisco Employee

Re: OSPF

You could configure router B as an ABR and configure the interface to router A as part of a totally stibby area. This way B would receive all networks from router A and A would only receive a default route from router B.

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

Re: OSPF

nittinigam you can follow hitter points .

it will work

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