In the field we see a lot of people struggle to find open TCP ports. Before Windows removed Telnet from the default Windows installation, a lot of people used it to determine if the port was ‘open’, or in other words testing port connectivity with Telnet.
But since the telnet program is not in the default Windows installation, I see many IT struggle to determine if a port connectivity is possible. I see some of them even add the telnet feature to enable the method again.
The way to go now is using the powershell command: test-netconnection
test-netconnection servername -port 1433
Test-NetConnection [[-ComputerName] <String>] -Port <Int32> [-InformationLevel <String>] [<CommonParameters>]