Using one ISP for particular traffic

Unanswered Question

I need your help. I have two ISP's going from my network to my other location. I want simply to route my SMTP traffic through ISP1 and all other traffic through ISP2. I don't want to use PBR on 6509 switch since that will include all ports on that vlan( unnecessary traffic inspection). IS there any way I can accomplish this. I a m using eigrp over GRE tunnel and also HSRP between these two routers.

I have this problem too.
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Steve Lyons Wed, 07/30/2008 - 18:44

If you are using BGP then you could pre-pend specific routes so they are preferred over a specific ISP. Below is a link to a document explaining Load Sharing with BGP in Single and Multihomed Environments:

After reading through the document it should give you ideas on how to pre-pend your smtp networks.

Steve Lyons - Cisco

rajib_das Wed, 07/30/2008 - 21:47

You can do it with EIGRP with route-map.

Using the accees-list first select the SMTP traffi.

using route-map set the next-hop to ISP1(say)

redistribute eigrp route-map in the router fastethernet interface.


Richard Burts Thu, 07/31/2008 - 03:38


With all due respect to my colleagues who have responded I interpret your question a bit differently than they do. The response from Steve would work if there were a distinct network for SMTP and a different distinct network for other traffic, but that is not how I understand your question.

And the response from rajib is inconsistent. The first suggestion:

Using the accees-list first select the SMTP traffi.

using route-map set the next-hop to ISP1(say)

is in fact a PBR solution (PBR is the only thing that allows you to set the next hop).

But then he suggests using the route map to control redistribution of EIGRP. But redistribution does not allow you to set the next hop.

If I understand your requirements correctly and you want to route the traffic differently depending on what kind of traffic it is (SMTP routed differently than other traffic) then the only solution that really does that is PBR.




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