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

ID: Q225503

The information in this article applies to:

SYMPTOMS

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.


CAUSE

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


RESOLUTION

A supported fix that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem. If you are not severely affected by this specific problem, Microsoft recommends that you wait for the next Windows NT 4.0 service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. 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:

http://www.microsoft.com/support/supportnet/overview/overview.asp
The English version of this fix should have the following file attributes or later:

   Date      Time                 Size    File name     Platform
   -------------------------------------------------------------
   05/18/99  01:32a                36,112 Raschap.dll   (x86)
   05/18/99  01:29a                57,616 Raschap.dll   (Alpha)

NOTE: If this product was already installed on your computer when you purchased it from the Original Equipment Manufacturer (OEM) and you need this fix, please call the Pay Per Incident number listed on the above Web site. If you contact Microsoft to obtain this fix, and if it is determined that you only require the fix you requested, no fee will be charged. However, if you request additional technical support, and if your no-charge technical support period has expired, or if you are not eligible for standard no-charge technical support, you may be charged a non-refundable fee.

For more information about eligibility for no-charge technical support, see the following article in the Microsoft Knowledge Base:
Q154871 Determining If You Are Eligible for No-Charge Technical Support


STATUS

Microsoft has confirmed this to be a problem in Windows NT 4.0 Service Pack 4.

Additional query words: ras chap router Remote Access Server 


Keywords          : 
Version           : winnt:4.0 SP4
Platform          : winnt 
Issue type        : kbbug

Last Reviewed: July 2, 1999