VPN with overlapping subnets

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VPN with overlapping subnets

L3 Networker

We have recently acquired 3 companies and all are using as their local subnet.  Now in a perfect world I could just go on-site and and change the addresses, but as well all know it's not and they have critical services running on AS400 systems that need to remain online during the transition.  So here is where NAT comes in.  I need to establish 3 IPSec tunnels and basically say that when traffic is going to 172.16.200.x (for example) go through tunnel.200 and change the IP back to 192.168.1.x.  And...when traffic comes from 192.168.1.x through tunnel.200 change to 172.16.200.x.  I know this can be done (as I have done it on Cisco and SonicWALL), but am just drawing a blank on how to set it up on the PA.  Any thoughts?


L6 Presenter

L5 Sessionator

Here is an old document, but the concept and the steps still holds good while building VPNs for overlapping subnets.


You will require Static Bi directional NAT configuration in order to have a seamless flow of traffic for these over lapping subnets, via the VPN



Their device only supports policy based VPNs not route based.  Would I do the same thing?


Doesn't matter. Policy or toute based VPN is important for VPN config after that, subnet overlapping will be solved by NAT.

Hope help.


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