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This question is prompted by another question here. Now I use teamviewer to connect to a Ubuntu desktop in a customer's LAN from my LAN. I get a password and access ID from him and connect, then use it to login to other ubuntu servers/machines using ssh or whatever commands/packages I need.

I am looking for an open source alternatives where I can do NAT Pass through on both ends (my router and customers router). If this can be accomplished by Free-NX, Remmina or VNC, can some one point to documentation on how to set this up?

Note: Port-forwarding from router at customer's router is not an option, so such solutions cannot be used.

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use SSH tunneling. it will require the least amount of installation and configuration of programs on the customer side and none on the server side

on the customer machine run the following command:

ssh -R 8080:localhost:80 username@YourPublicIP

in the example above. the local port 80 on the customers machine will be accessible/forwaded to the machine with YourPublicIP even though the customers machine is behind NAT.

In your scenario you can ask the customer to press a "link" to a script you have installed for him/her. running the command above.

If your customer is using Windows. You can a do the above with a windows ssh client like putty

The customer will need a password to your machine unless you configure the customer to authenticate with key based authentication

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In my question, the source IP (my machine) also has a local IP (say in my network) behind a router and destination machine also has a local IP (say at customer network). Both routers WAN interface will have a public IP (dynamic in many cases as happens in India). In your example, then How I will connect to customer machine ? Sorry, I am a new-bie in port forwarding options of ssh. – Jamess Aug 8 '12 at 12:50

Take a look at this page. I am sure you find a solution there.

Another way to address your problem is to install a VPN software like hamachi.

Hope that helps.

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I already reviewed this page. It gives list of options which have NAT pass through. But I could not find specific examples from my search on how to accomplish it with each of it. – Jamess Aug 8 '12 at 12:46

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