Hi, we have dropped our ADSL connection at one office as we were paying for a phone line and ADSL only to get less than 1 meg as we are so far from the exchange. We didn't use the phone as we have a VOIP system.

We now use a three.co.uk PAYG dongle, we get a faster connection than our ADSL line and can hold two simultaneous VoIP calls at the same time.

The only downside is that we have lost our site to site VPN, I know mobile broadband typically uses NAT and I'm sure that is where we are falling down, anyone have any idea's about setting it all up.

I have a Vodafone 3G stick and when I looked into my VPN issues found the same as you (a private IP from the stick). I found that Vodafone offer a ‘business grade’ service for not much more cost which avoids the NAT problem, so maybe Three do also?

We are based out in the Fens in rural Cambridgeshire and Three is about the only network with decent 3G coverage.

I have tried ploughing through the website and could n't find anything and when I spoke to the sales people I got the reply 'what is a VPN'

I have managed to get the VPN to work when the router behind the dongle is set to dial out, but can't initiate a VPN when the remote site wants to get back in.

I think voda offer a different set of settings for it you wanted to use VPN, I know this was the case with the cisco vpn client from users laptops...

Perhaps 3 offer something similar? Might be worth a google...

With the 3G connection, do you get a 10.x address or a public one probably in the 9x.x.x.x range? When I've used a 3 modem it's always had the public address which worked well for connecting in to.
Have you got the APN set up on the router as "3internet"? I've seen it give a private address out with no APN entered.

I had a private range IP beginning with 10, I have now changed the APN as suggested and I now get an IP address beginning with 94.

I will see how we get on with that when our dyn.dns address up-dates etc.

Many thanks for all your help.