You Can Connect with Telnet to Any IP Address on Port 389 (315846)


The information in this article applies to:

  • Microsoft Windows XP Professional
  • Microsoft Windows XP Home Edition
This article was previously published under Q315846

SYMPTOMS

If you turn on the Internet Connection Firewall feature in Windows XP and you try to use Telnet to connect to any valid IP address on port 389, the Telnet connection appears to be made successfully, even if the host is not listening on that port. The output from the netstat command shows that no local service is listening on port 389. This behavior also occurs with ports 21, 1002, and 1720. This behavior does not occur if you do not turn on the Internet Connection Firewall feature.

CAUSE

If the Internet Connection Firewall feature is on and you try to connect with Telnet to port 389, you actually connect to the local Lightweight Directory Access Protocol (LDAP) proxy that is part of the Firewall service.
Modification Type:MajorLast Reviewed:3/14/2002
Keywords:kbenv kbprb KB315846
©2002 Microsoft Corporation. All rights reserved.