MD-5 CHAP Authentication Does Not Work with Windows NT 4.0 Service Pack 4

After you apply Windows NT 4.0 Service Pack 4 to your remote access server computer, CHAP-MD5 authentication cannot be used for incoming dial-up connections. Client computers that attempt to authenticate using CHAP-MD5 can no longer connect to the remote access server.

No valid CHAP challenge was being sent by the RAS computer.

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or the individual software update. For information on obtaining the latest service pack, please go to:

• http://www.microsoft.com/downloads/details.aspx?familyid=E396D059-E402-46EF-B095-A74399E25737&displaylang=en/ (http://www.microsoft.com/Windows/ServicePacks/) -or-
  
  
• 152734  (http://support.microsoft.com/kb/152734/EN-US/ ) how to obtain the latest windows nt 4.0 service pack

For information on obtaining the individual software update, contact Microsoft Product Support Services. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows NT Server version 4.0, Terminal Server Edition Service Pack 6.