I am trying to run VNC at 5900, but allegedly some process is holding it, thus vnc complains: NOT accepting connections.

how to fix that

  • Is it already installed as a service, but you're launching it as a client? The service will already have the port open.
  • Is the built-in firewall interfering?
  • As a temporary work-around, have you considered just bumping the display port by 1? This serves as a diagnostic - if you can connect to {host IP}:5901 just fine, then most likely the port really is taken. If that host-port combo also fails, then it's more likely your firewall is causing you grief.

start -> run -> cmd -> netstat -b

  • 1
    you can use netstat -o as well in combination with task manager.
    – Keith
    Jul 31 '09 at 2:32

TCPView from sysinternals - http://technet.microsoft.com/en-us/sysinternals/bb897437.aspx

The entire sysinternals suite is highly recommended.


download and run cports which is available here. this will tell you what process is listening on what ports.


sure there are other tools but http://www.netlimiter.com/ is one tool i have used in the past

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