Is it possible to get incoming connections? I wanted to access an OpenVPN on a machine that uses a 3G WAN connection but when I've used port forwarding sites I can't find any open ports. Is this not possible on AIS 3G?

edit: typo

To my knowledge all 3G and CDMA systems do not give you a public IP address, but only a private IP address in the range 10x.y.z, and thus you cannot open ports for torrents or other access.

There are limited ways round it depending on what you want to do, for example use the Likes of Team Viewer for your remote access, but it is a BIG drawback for many things

This is out of my competence, but would it be possible to open VPN tunnel to server on the unnatted internet and then access the the natted network through it?

There are VPN services that will give you a public IP address (although still port forwarded over a NAT), such as TuVPN.

This is out of my competence, but would it be possible to open VPN tunnel to server on the unnatted internet and then access the the natted network through it?

I think you are asking for what I have managed (with a lot of help from an IT Guru on this project.

I wanted a VPN tunnel to my home setup (CAT CDMA) whist away. I could use the likes of Team Viewer to access my computer but that would not give me access to my webcams or NAS unless my computer was turned on.

My solution was to buy 2 linksys routers and install DD-WRT open source firmware and then Open VPN on them. The router in Thailand on the CAT CDMA network then creates a tunnel to my router here which has a normal public IP address which you get with a wired internet connection.

In theory this gives me full access to my home IT gear including all PCs web-cams and NAS storage.

I state "in theory" because although it worked I found it very slow. This should not be the case but limited time on my last leave did not allow me to get everything running 100%

Instead of going the DD-WRT route, I am told there are also Cisco routers available with built in VPN functionality but they are not available in my current work country and I needed a solution I could program and test before going to Thailand.