Netgear Router, Port 5900, Not Working

Michael Milette tng "at"
Sun, 06 Jan 2002 04:55:31 +0000

At 06:07 PM 2002-01-05, you wrote:
>I have a Netgear Router on my DSL connection, I have routed port 5900
>to the machine where VNC Server is running ( Win98) with the latest
>download of VNC and I get no connection.
>If I connect across the local LAN using the 192.xxxx address, it works
>just fine so I know VNC is working.

Here are some suggestions:

1) When attempting to connect to your machine over the Internet, you must 
specify the IP address of your router, not the IP address of the host machine.

2) Make sure your VNC host server is not being assigned a dynamic IP 
address. Otherwise, the IP address of your machine at work may change by 
the time you get home in which case the configuration on the firewall would 
become invalid.

3) Telnet to your routers Internet IP address from home. Specify the IP 
address on the Internet as the host name, and 5900 for the port number. You 
should see "RFB 003.003" appear on the screen. If you do, VNC is responding 
correctly and the problem may be at the client end. If you don't, the 
problem could be either on the router or the host machine.

4) I know this is probably blatantly obvious but make sure your host 
computer is powered on when you try to connect. It is conceivable that 
someone is going around powering off the computers before leaving at night 
after you leave and turning them back on in the morning before you arrive.

5) If you are using the Java VNC Client from within a web browser, you will 
need to forward port 5800 as well as 5900.

6) Make sure VNC is waiting for a connection on port 5900 (display value 
should be "0").

7) Make sure nobody else is also connected to your host machine at the same 

8) Find the following registry key exists. This registry key basically 
restricts which IP address can connect to your machine. If it does exist, 
export the branch (just in case) and then delete the AuthHosts key:


9) Make sure your router is forwarding incoming (sometimes also called 
inbound) port 5900 to port 5900 at the LAN IP address (192.x.x.x) of your 

10) Come back after you have checked the above and ask again. If and when 
you do, please also include answers to the following questions:

         a) What exactly is the error message you are getting? Even when 
there is no connection, you still get an error message though it may take a 
few minutes.

         b) What is the speed of your clients connection? If it is too 
slow, VNC can actually crash your host computer if it takes too long to 
download the initial screen to the client. TightVNC has recently fixed this 
bug and may be a better alternative for slow modem connections.

         Hope you find some of this useful. Have a great day!

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