Event ID 8146 is logged in the application log every five minutes after the Exchange 2003 SP1 MSADC component experiences LDAP communication problems (891860)

SYMPTOMS

If you configure one or more connection agreements between a computer that is running Microsoft Exchange Server 2003 Service Pack 1 (SP1) and Active Directory directory services, the following symptoms occur:

The Active Directory Connector (ADC) may stop processing the Recipient Connection Agreement.
An event that is similar to the following is logged in the application log every five minutes:
Event Type: Error
Event Source: MSADC
Event Category: Replication
Event ID: 8146
Date: 9/3/2004
Time: 11:57:51 AM
User: N/A
Computer: ComputerName
Description:
An operation on server ComputerName returned [0xc] Unavailable Critical Extension. ConnectionAgreementName has stopped.

CAUSE

This problem occurs because the Microsoft Active Directory Connector (MSADC) component cannot use the Lightweight Directory Access Protocol (LDAP) version 3 protocol to communicate with Active Directory after it tries to use the LDAP version 2 protocol.

By default, the MSADC uses LDAP version 3 to communicate with Active Directory. For backward compatibility reasons, MSADC may try to use an earlier version of LDAP if it experiences problems during the communication session.

However, earlier versions of LDAP do not support some critical LDAP extensions that are required by MSADC. The event message that is mentioned in the "Symptoms" section is logged in the application log when MSADC tries to use those extensions when it communicates by using LDAP version 2.

When you restart the MSADC service, the MSADC component uses LDAP version 3 to communicate with Active Directory.

RESOLUTION

Service pack information

To resolve this problem, obtain the latest service pack for Exchange Server 2003. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

836993 How to obtain the latest service packs for Exchange Server 2003

Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Microsoft Exchange Server 2003 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

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 usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Prerequisites

No prerequisites are required.

Restart requirement

You do not have to restart your computer after you apply this software update.

Hotfix replacement information

This hotfix does not replace any other software updates.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

   Date         Time   Version       Size     File name
   ----------------------------------------------------
   11-Feb-2005  04:58  6.5.7232.80   697,344  Adc.exe

MORE INFORMATION

For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates