Test the functionality of port 3389 by using Telnet Just try to telnet to the port from the Client. You can run a simple troubleshooting test to make sure the Client can connect to the port. A common problem in a WAN environment is that a firewall or other network filter prevents connectivity with this port. Terminal Server Clients use TCP port 3389 to communicate with Terminal Server. This article describes how to use Telnet to test port 3389 functionality.
Use Telnet to test port 3389 functionality
