Microsoft KB Archive/218955

= XFOR: Chat Service Fails DPA Authentication with 9-Character User Names =

Article ID: 218955

Article Last Modified on 10/26/2006

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APPLIES TO


 * Microsoft Exchange Server 5.5 Standard Edition
 * Microsoft Commercial Internet System 2.0

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This article was previously published under Q218955





SYMPTOMS
Chat clients with nine character user names get "Login Failures" when they try to connect to Chat servers using DPA authentication.



CAUSE
The problem occurs because chat clients encode the length of a nine character username as a '\t' per the IRCX spec; the IRCX specifies that all TAB (ASCII TAB = 0x09) characters are to be escaped as a backslash followed by a 't'. In this case when the Chat service decoded the authentication message from the client, it incorrectly decoded '\t' as 0x07 (the ASCII BEL code). The resulting decoded string length of 0x07 resulted in the nine character user name being truncated to seven characters long, thus failing DPA authentication.



RESOLUTION
To resolve this problem, obtain the latest service pack for Exchange Server version 5.5. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

191014 XGEN: How to Obtain the latest Exchange Server 5.5 Service Pack

Component: Chat Service



STATUS
Microsoft has confirmed that this is a problem in the Chat Service that is included with the Microsoft products listed at the beginning of this article. This problem was first corrected in Exchange Server 5.5 Service Pack 3.

Keywords: kbhotfixserver kbqfe kbbug kbfix kbqfe KB218955

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