Unanswered Question
Jun 10th, 2008

I am looking to run a FWSM in my 6509 with multiple contexts in routed mode. I have routers on both sides of the FWSM that need to communicate with a dynamic routing protocol. Is there a way to configure the FWSM to allow the routing protocol to pass through between the routers? I have seen examples running OSPF on the FWSM, but that is not supported in multiple contexts. I have also seen examples to allow OSPF to pass through in transparent mode, but not in routed mode. I can't seem to find anything that shows what I am looking for. Thanks

I have this problem too.
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Jon Marshall Tue, 06/10/2008 - 08:33


Depends on the routing protocol. For example BGP can peer with routers that are more than one hop away so you could use BGP.

But EIGRP/OSPF etc. form neighborships with other routers on the same subnet. So unfortunately because the FWSM is a L3 hop in routed mode then it will not work.

As you say, transparent mode is really the only thing you could do as multiple context mode does not support a dynamic routing protocol.

One things you may be able to try but would obviously need testing is to have a transparent context specifically for the 2 routers to exchange routes. But this may or may not fit with your topology.


Syed Iftekhar Ahmed Tue, 06/10/2008 - 10:23

In routing mode you can pass on routing updates (and for that matter any multicast) using GRE tunnels.


Farrukh Haroon Tue, 06/10/2008 - 11:13

The GRE option is there, but to be honest you should value the KISS rule as much as you can. Making your network unnecessarily complex can only harm you in the long run.

I had a discussion with a very talented CSE working with Cisco Systems and he recommended using transparent mode in such situations.




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