Where is Mysql-server port in openbsd

The answer can be found in this wikipedia article:

Applications implementing common services often use specifically reserved, well-known port numbers for receiving service requests from client hosts. This process is known as listening and involves the receipt of a request on the well-known port and reestablishing one-to-one server-client communications on another private port, so that other clients may also contact the well-known service port.

Also, from this article on Berkeley sockets on wikipedia.

When an application is listening for stream-oriented connections from other hosts, it is notified of such events (cf. select() function) and must initialize the connection using the accept() function. Accept() creates a new socket for each connection and removes the connection from the listen queue.

Nope. Either you're walking them through installing the telnet client native to Windows, or you're having them install Putty or a similar app. The functionality was deemed a security risk and so was turned off.