Addressing Question about Customer/Vendor Site-to-Site VPNs

Hey Everyone,

We have a couple site-to-site VPNs that we use for our customers. We typically provide a set of specifications regarding algorithms and key sizes, but tunnel addressing as always been something unique and negotiated for each customer.

I know this is decided on a case-by-case basis, but when you set up a VPN with an external business (vendor / customer), do you typically provide:

• The literal IP / Subnets used on your network (providing there's no overlap between both networks)
• A translated internal IP for the traffic to pass through
• A translated external IP for traffic.

We've tried setting up tunnels using a translated internal IP on both sides of the VPN to prevent addressing conflicts, but we typically run into issues with customers not knowing / unable to set up an address translation. This makes me wonder if it's not commonly used.

Thanks