DCDiag (included in Windows Server 2003 Support Tools) reported a stange error at a site the other day:
C:>dcdiag
Domain Controller Diagnosis
Performing initial setup:
***ERROR: There is an inconsistency in the DS, suggest you run dcdiag in a few moments, perhaps on a different DC.
***ERROR: There is an inconsistency in the DS, suggest you run dcdiag in a few moments, perhaps on a different DC.
This was accompanied by the following event in the Directory Services log on all DCs in the forest:
EntryType : Error
EventID : 1550
Message : The following site has no NTDS Site Settings child object.
EventID : 1550
Message : The following site has no NTDS Site Settings child object.
Site: CN=SITE1,CN=Sites,CN=Configuration,DC=domain,DC=com
User Action
Create an NTDS Site Settings object for this site using Active Directory Sites and Services.
Category : Knowledge Consistency Checker
CategoryNumber : 1
ReplacementStrings : {CN=SITE1,CN=Sites,CN=Configuration,DC=domain,DC=com}
Source : NTDS KCC
TimeGenerated : 11/28/2007 5:41:06 PM
TimeWritten : 11/28/2007 5:41:06 PM
UserName : NT AUTHORITYANONYMOUS LOGON
Category : Knowledge Consistency Checker
CategoryNumber : 1
ReplacementStrings : {CN=SITE1,CN=Sites,CN=Configuration,DC=domain,DC=com}
Source : NTDS KCC
TimeGenerated : 11/28/2007 5:41:06 PM
TimeWritten : 11/28/2007 5:41:06 PM
UserName : NT AUTHORITYANONYMOUS LOGON
Sure enough, the NTDS Site Settings and, altough not reported in the log, the License Site Settings object were missing from the site. After I recreated them and replicated the forest, DCDiag ran successfully and the messages in the Event log dissapeared.
As a footnote, the missing NTDS Site Settings object also resulted in the site not having an ISTG server and thus not being able to create inter-site replication objects. The site could only replicate with the other sites because of the existing connection objects, new objects could not be created.