IP forwarding over a VPN

[Gihzmo]

Hello,

We are trying to forward an IP address of an AS/400 from one side of a VPN tunnel, to the other. Basically we are moving the AS/400 from one side of the VPN, to our data center on the other. The problem is, all of the clients have the old IP address in their software, so we are trying to come up with a way to forward or proxy any request bound for its old IP address and forward it to the new IP address. I thought about using nat but I don't see how that will work, and I could not get it to, because the VPN would have to be set up to allow the IP address back to itself.

Just as a quick diagram:



This is the current setup:

User -- MPLS -- > AS/400 (OLD IP address)

What we want to do is:

User -- MPLS -- > ???? (Old IP address) -- > Cisco 3000 VPN concentrator --> Cisco PIX 520 --> AS/400 (New IP address)

 

[plshlpme]

so wil you be moving the whole subnet that the as400 is on to the new location?

if that is the case then you should be able to just use a static route to show that subnet in the new location...

 

[Gihzmo]

No, we will be changing the address of the AS/400 to our data center's network IP. I talked to cisco about it and they suggested basically using routes to route traffic for that IP address to the concentrator, then changing the tunnel to send the data for that address over then vpn, and then natting it on the PIX 520.