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How can I use VNC through a firewall or NAT proxy?

This article is specifically meant to deal with the problem of allowing a remote host to take control of a VNC Server which cannot use a listening port. This is a common problem in a NAT environment.

The solution is a Listen Mode for the VNC client. Make use of it in two steps:

1. On the Master machine (the one you want to remotely control from), you must run the VNC Client in Listen Mode. There might be an icon in the Start Menu, or just run vncviewer -listen.
2. One the Slave machine, make sure the VNC Server is running. Right-click on the Server's tray icon, and select either "New Connection" or "Add New Client". In the dialog that opens, type in host-address and port/screen number to connect to on the Master.

Note: The default TCP/IP port is 5500 (corosponding to display 0). To use a TCP Port use: hostname::port (note double-colon!). To use the display port use: hostname:display (only a single colon).

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