Windows NT
If the first word is supposed to be what and not when then the answer is Server Core.
Troubleshooting options for Windows servers will depend on the version of Windows you are running, so it will first be important to identify the version you are currently working with. Once you have done that, support.microsoft.com provides an array of options to help get your server back up and running in not time.
There are several common reasons you might be unable to connect to a Terraria server. First, ensure that you have the correct IP address and port number, and check if the server is online and not full. Additionally, verify that your firewall or antivirus software isn't blocking the connection. Lastly, ensure you're using the same version of the game as the server, as version mismatches can prevent a successful connection.
Windows 2000 was the first
Windows NT 3.1
windows 2.0
Windows XP
The first version was available for Windows Me in 2000.
The first one.
TCP/IP first
The first version of Paint was introduced with the first version of Windows, Windows 1.0 released on 20 November 1985.
Windows for Workgroups