Dial-Up or PPTP Client That Uses MSCHAPv1 Authentication Cannot Establish 40-Bit or 56-Bit Encryption Connection (254177)


The information in this article applies to:

  • Microsoft Windows 2000 Advanced Server
  • Microsoft Windows 2000 Professional
This article was previously published under Q254177

SYMPTOMS

On a dial-up or Point to Point Tunneling Protocol (PPTP) client that is specifically configured for MS-Challenge Handshake Authentication Protocol Version 1 (MSCHAPv1), you cannot establish a 40-bit or 56-bit encryption connection.

CAUSE

This behavior occurs when a password is longer than 14 characters. MSCHAPv1 does not support longer passwords. Note that this does not affect connections made using MSCHAPv2, which is the default in most cases. Also, this restriction does not affect 128-bit connections.

RESOLUTION

To resolve this issue, use a password no longer than 14 characters to allow dial-up or PPTP clients that are specifically configured to use MSCHAPv1 authentication to establish a 40-bit or 56-bit encryption connection.
Modification Type:MajorLast Reviewed:11/4/2003
Keywords:kbprb KB254177
©2003 Microsoft Corporation. All rights reserved.