Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I've vnc-java running on an Ubuntu box, with the IP address, using port 5800 (because port 5900 is being used for normal VNC).

If I connect to using another computer on the network, I can use VNC fine.

Using, I find out what my IP address from the outside world is, and if I go directly to that, I get to access my modem/router. If I try to navigate to that IP address, with ':5800' on the end, I get a "This web page is not available." error.

I have port forwarding set up in the router as follows:

Application Name    External Packet             Internal Host
                 IP Address     Protocol    Port    IP Address      Port    
VNC                  ALL        TCP/UDP     5800    5800

What else do I need to do to get this to work?

share|improve this question
I'm wondering if the modem/router was provided by the ISP and they may have locked things down or maybe running some kind of server side firewall. Also it sounds like you can get to the modem/router's management interface from the public address, if so, that sounds like trouble. – Scott McClenning Jan 22 '10 at 6:45

Your router is probably forwarding packets received on its external interface to, if you are accessing it internally then it won't forward. This is common with most home routers.

You can test for port forwarding using a site like Can You See Me?

share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .