Assume that you use one of the following account mapping methods together with the altSecurityIdentities attribute to map a user to a certificate in Microsoft Exchange Server 2010:
Public Key SHA1 Hash
Subject Key Identifier
Issuer & Serial Number
In this situation, the following event is logged in the Application log. Additionally, some Exchange Server 2010 functionality may not work as expected for the user.
Log Name: Application Source: MSExchange ADAccess Event ID: 2160 Level: Warning Computer: Exchange.domain.com Description: Process w3wp.exe (). Recipient object CN=<User>,OU=Users,OU=site,DC=lab,DC=contoso,DC=com read from DC.domain.com failed validation and will be excluded from the result set. Set event logging level for Validation category to Expert to get additional events about each failure.
This issue occurs because Exchange Server 2010 does not support the account mapping methods that are listed in the "Symptoms" section.
To resolve this issue, use the following account mapping methods that are supported by Exchange Server 2010:
Subject and Issuer Name X509:<I>issuer<S>subject
Active Directory 2008 enables alternative account mappings by using the altSecurityIdentities attribute. This attribute contains the user’s certificate information that is used by the Kerberos Authentication service to identify the associated Active Directory user account.
For more information about how to map a user to a certificate, go to the following Microsoft website: