networking - In Windows, using the command line, how do you check if a remote port is open?

What is a simple way in Windows to test if traffic gets through to a specific port on a remote machine?

Answer

I found a hiddem gem the other day from Microsoft that is designed for testing ports:

Portqry.exe

"Portqry.exe is a command-line utility that you can use to help troubleshoot TCP/IP connectivity issues. Portqry.exe runs on Windows 2000-based computers, on Windows XP-based computers, and on Windows Server 2003-based computers. The utility reports the port status of TCP and UDP ports on a computer that you select. "