Do I need to open a port for a TCP connection?

Question

Windows Server

So, the question is simple: do I need an open port in order to connect to a computer via TCP?
If not needed, what is needed for this (From the point of view of the server)?

Answer 1

You need to open the port. Even if you use UDP.
The port must be opened both in the program and in the OS firewall (on the listening side).