3. Check whether the server's TCP/IP Port is configured as port 1433. Check the TCP/IP attribute in the enabled protocol in the server network utility to make sure that the default port is 1433 and the check box of the hidden server is not checked.
In fact, it is acceptable if the default port is modified. However, when the client performs a telnet test, the server port number must be consistent with the port number configured on the server. If the "Hide server" check box is selected, it means that the client cannot see this server by enumerating the server, which protects the server but does not affect the connection, however, the default port of TCP/IP protocol is implicitly modified to 2433, which must be changed when the client is connected.
Then perform the telnet server IP 1433 test, and the cursor will not stop flashing in the upper left corner after the screen flashes. Congratulations, you can start to connect to the Enterprise Manager or query analyzer immediately.
Reference http://xu020408.blog.163.com/blog/static/2654892010025112485/