VNC FAQ-o-Matic : VNC and Firewalls : How should I setup my firewall to work with VNC?
If you’ve administrative control over your firewall/router that protects your collection of VNC servers, setting up the firewall so that any or all of your VNC servers are accessible from the outside is fairly straightforward. Suppose, for example, you have 5 PC’s, all of which are running VNC servers, and you want to be able to access them from the “outside”. You’ll need to make 5 “port forwarding” entries: 1. External TCP port 5900 to your first PC’s port 5900 2. External TCP port 5901 to your second PC’s port 5900 3. External TCP port 5902 to your third PC’s port 5900 4. External TCP port 5903 to your fourth PC’s port 5900 5. External TCP port 5904 to your fifth PC’s port 5900 Then if you point a VNC viewer to your external IP address, “Display 0” will reach your first PC, “Display 1” will reach your second, etc. Keep in mind the relationship: “Display N” = “TCP port 5900+N”. If you wish to connect with the web-browser client, you’ll need to make three additional adjustments. First,
