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New Member

source route or tracking?

Is you have a DR site with two routers at the site (no HSRP), the ethernet interfaces of both routers on the same subnet.

Each router has a different path to the Main site, path A and path B, no routing protocol on the routers.

Is it possible to configure the routers at the DR site to send the traffic back to the main site on the same path it took to get there, no matter which path it takes?

Traffic arrives on path A, send it back Path A, if it arrives on Path B, send it back Path B

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Re: source route or tracking?


I do not see a way to do what you are describing. The major difficulty is that the data packet arrives via path A/B and is forwarded to the destination. The destination generates a response. But when the response gets to the router there is no ability to know what the arrival path was. The router does not maintain state for packets it has already forwarded. And the destination host has no way to know the arrival path - and very little way to signal what the return path should be.

The closest thing that I can think of to your suggestion is some kind of policy routing implementation. This could specify that certain types of traffic would take path A while other types would take path B. You could then have the routers send return traffic over the appropriate path.

I do not think that this solution is perfect. But it is probably as close as you are likely to get.



New Member

Re: source route or tracking?

Thanks for the reply

Re: source route or tracking?


the only way I can imagine is to use NAT on both pathes which would create an entry for each communication. Whether this is really what you want (NAT) I cannot tell. What is the problem with normal routing/load sharing you encounter or try to fix?

Regards, Martin

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