If you are using a wireless router for a DSL connection, I would say there is about a 95% chance that you are using NAT. Most DSL providers will not allocate public IP's unless you pay for them seperately, and also many ISP's don't even have the option of requesting additional IP's. THe public IP they give you is taken by your DSL router, and therefore you have to use NAT or more commonly PAT (port address translation) for additional machines inside the network, in which case you will have VPN problems.

So os1, you are correct in the fact did he did not specifically mention NAT. It was an assumption on my part based on many similar experiences in the past with VPN's and DSL routers.

captfb, you should be able to tell what kind of VPN (likely IKE) in the client configuration properties. It may also help if you could say what kind of VPN device you are trying to connect to. If it is a Cisco (which I am assuming) the easiest way to troubleshoot it woud be to call TAC 800-553-2447 (as long as you have a valid support contract). Unless of course you want to give me access to your VPN concentrator . Which I wouldn't recommend.

Hope this helps at least a little