When working with multiple servers selecting a port you need for a specific server can be quite challenging when other applications are running and have already been using those ports.
In such situations of a port been blocked we are always greeted with familiar messages as below.
This is normally caused when one application process is already bound to a port. Another instance is a connection that has been terminated but the port is still in TIME_WAIT state and is ready to be terminated.
1. Netstat approach – Using a command line figuring out the processes bound to a port.
Finding out network information and port bindings can be done using the following command in the command prompt.
netstat -a -b
2. Using a tool such as TCPView
The Microsoft TCPView is a quick and handy GUI tool for checking port bindings, network state, and other information related to network connections already established.
Common culprit for port 80 binding – Skype
Normally Skype binds to port 80 and port 443 by default and this prevents other servers from connecting to port 80.
To change the default port 80 binding of skype follow the steps below.
1. Tools >Options.
2. Select Advanced from the menu left.
3. Next select Connection from the sub list in left menu area.
4. Tick of “Use port 80 and 443 as alternatives for incoming connections.”