Depending on what you are trying to do, the answer is maybe. For VPN connections to a computer behind the Extreme from another computer else where the ports must be forwarded to allow it to work. The same goes the other way around. The Extreme in and of itself is not a VPN server but does allow you to share USB attached disks via WAN if thats all you want.Can I set up a VPN with the current Airport Extreme? Or is that functionality not possible?
I think running Back to My Mac to connect to shared drive on Extreme, comes close to that (Extreme becomes the IPsec tunnel endpoint). But just for that particular connection, as I understand.It is not possible to have a VPN server running on an Airport Extreme. It does however allow VPN pass through for outgoing VPN connections.