I need to use VNC to control a computer behind a NAT. I have no access to the remote router, but I can have the person sitting in front of the computer follow very simple instructions. I'm also behind a NAT, but I can set up port forwarding if needed. The connection is Win to Win and I was thinking of using UltraVNC. I have no previous experience with VNC. So far from what I've read I've got two ideas:

  1. Setup port forwarding on my end and have client connect to my computer running the VNC viewer.
  2. Try using the UltraVNC NatToNat add-on.

Is number 1 possible and realistic? Any kind of documentation for it from the clients pov?

How does #2 work? Are there any public UltraVNC Nat Helper servers?

Any other ideas? This is a one off thing so I don't want to get to involved or complicated.


If you are willing/able to use an alternative solution, I suggest teamviewer.

It's free for non commercial usage. Usage is really simple.

  1. Download/Install the software
  2. Start the Client, and give the other user the teamviewer ID and password ( both are visible on the main screen)

Other user can use given user/password combo to remotely connect and control the PC.

  • I've used this many times for quick remote sessions. – LawrenceC Sep 7 '12 at 12:35
  • Awesome, this look like exactly what I'm looking for. – Robert S. Barnes Oct 11 '12 at 18:10
  • Except you might not be able to see if you're installing "personal" or "commercial" version, and then after 30 days TeamViewer might determine you're using it commercially, and then you will have to pay. – sdbbs Feb 21 at 8:37

You could connect through a reverse SSH tunnel. Configure your router to forward some port (say 2222/tcp) to a local SSH server on your side. Have the remote user establish a reverse SSH tunnel from the host running the VNC server to your public IP address (a.b.c.d):

plink -R 5901: -P 2222 -L USER a.b.c.d

Once the tunnel is established, you can connect with the VNC client your SSH server's IP address, e.g.


or (when the SSH server is running on your workstation


The NatToNat add-on uses a similar (though slightly different) approach.


When try to help my 80 year old Dad remotely I have used a VPN to avoid all the NAT/Firewall etc issues. I used Logmein Hamachi to create a virtual network then got him to install Hamachi and join the network with the user name/password. Simple and hopefully secure connectivity.

I then got him to install UltraVNC Server whilst I installed the viewer. Connect using the VPN IP address - voila. Any remote control software will then run over the VPN, it doesn't have to be VNC.

  • Sounds interesting and cool, but I think the teamviewer solution is probably more suited to my situation - I'm also helping out my Dad :-) – Robert S. Barnes Oct 11 '12 at 18:11

zero tier is another alternative to hamachi which is open source. You can use it to easily get the computer onto a shared vpn which you can then remote desktop or ssh into from there.

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