This article was previously published under Q303448
This article has been archived. It is offered "as is" and will no longer be updated.
For additional information about a similar problem that may occur in Microsoft Exchange 2000 Server, click the following article number to view the article in the Microsoft Knowledge Base:
303450 XADM: Exchange 2000 Server LDAP Service Denial of Service Occurs When LDAP Is Handling Code
If the Exchange Server Lightweight Directory Access Protocol (LDAP) service receives a specially malformed LDAP search, the Exchange 5.5 Directory service (DSAMAIN) may stop responding (hang).
A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Microsoft Exchange Server 5.5 service pack that contains this hotfix.
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 about support costs, visit the following Microsoft Web site:
NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.
The English version of this fix should have the following file attributes or later:
NOTE: Because of file dependencies, this fix requires Microsoft Exchange Server version 5.5 Service Pack 4.
Microsoft has confirmed that this is a problem in Microsoft Exchange Server version 5.5.