DOCUMENT:Q187628  11-DEC-2001  [winnt]
TITLE   :Using Telnet to Test Port 3389 Functionality
PRODUCT :Microsoft Windows NT
PROD/VER:winnt:4.0
OPER/SYS:
KEYWORDS:

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Windows NT Server version 4.0, Terminal Server Edition 
-------------------------------------------------------------------------------

SUMMARY
=======

Terminal Server Clients use TCP port 3389 to communicate with Terminal Server. A
common problem in a WAN environment is that a firewall or other network filter
prevents connectivity with this port. You can run a simple troubleshooting test
to make sure the Client can connect to the port. Just try to telnet to the port
from the Client.

To test the functionality of port 3389, use this command from the Client:

   Telnet tserv 3389

where "tserv" is the host name of your Terminal Server.

If telnet is successful, you simply receive the telnet screen and a cursor. On
the Terminal Server, Terminal Server Administration will show a blue computer
icon with no other information. The Telnet connection will also consume an idle
session.

The Terminal Server should disconnect the connection after a few minutes. Or, you
can disconnect using Telnet.

This test tells you that you can connect over the port.

If Telnet reports that you cannot connect, there are several possible reasons:

1. If you can connect by replacing "tserv" with the Terminal Server's IP address
   but not the host name, you may have a DNS or WINS resolution problem.

2. If you can connect when "tserv" is the host name, but cannot connect when
   "tserv" is the computer name, then you may have a NetBIOS name resolution
   issue with WINS or an LMHOSTS file.

3. If you cannot connect when "tserv" is the IP address, the host name, or the
   computer name, then it is likely that port 3389 is blocked somewhere in your
   WAN.

Additional query words:

======================================================================
Keywords          :  
Technology        : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTS400search kbNTTermServ400 kbNTTermServSearch
Version           : winnt:4.0
Issue type        : kbinfo

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2001.