Using VNC to Control PC behind NAT

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:

Setup port forwarding on my end and have client connect to my computer running the VNC viewer.
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.

Robert S. Barnes

Posted 2012-09-06T17:50:22.667

Reputation: 609

Answers

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

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

Download/Install the software
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.

bbaja42

Posted 2012-09-06T17:50:22.667

Reputation: 2 815

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 – 2019-02-21T08:37:22.827

I've used this many times for quick remote sessions. – LawrenceC – 2012-09-07T12:35:09.710

Awesome, this look like exactly what I'm looking for. – Robert S. Barnes – 2012-10-11T18:10:34.743

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 5901:127.0.0.1:5901 -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.

vncviewer 192.168.23.42:1

or (when the SSH server is running on your workstation

vncviewer 127.0.0.1:1

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

Ansgar Wiechers

Posted 2012-09-06T17:50:22.667

Reputation: 4 860

To whoever finds this: here's some more detailed information https://blog.trackets.com/2014/05/17/ssh-tunnel-local-and-remote-port-forwarding-explained-with-examples.html (scroll down to Remote port forwarding and make sure to set GatewayPorts yes otherwise the server's end will bind to 127.0.0.1 and 0.0.0.0 or \* won't help)

– aexl – 2018-08-03T20:07:07.133

I'm looking for a reasonably simple Win To Win solution. – Robert S. Barnes – 2012-09-07T06:29:45.700

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.

Bish

Posted 2012-09-06T17:50:22.667

Reputation: 403

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 – 2012-10-11T18:11:46.600

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.

Pellet

Posted 2012-09-06T17:50:22.667

Reputation: 101