Why does "Test Socket" button report "Address Already in use:" while the channel is running?

Question

When a channel with a source node set as Server Socket is running and I click on the “Test Socket” I receive an error "Address Already in use:". However when the channel is not running it reports “Server socket created.”

Answer 1

A server socket is setup as a listener. This means that it will open a port on the host server to receive data. You can only have one listener per port number. The reason it reports "Address Already in use:" is because when the channel is started that port is open and in use. When the channel is stopped it is not in use and the test successful and will report “Server socket created”.