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Duplicate names in AD causing kerberos errors

Posted on 2012-03-21
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Last Modified: 2012-03-29
I get this error twice every hour or so on all my dcs.
The KDC encountered duplicate names while processing a Kerberos authentication request. The duplicate name is MSSQLSvc/servername.domain.com:1433 (of type DS_SERVICE_PRINCIPAL_NAME). This may result in authentication failures or downgrades to NTLM. In order to prevent this from occuring remove the duplicate entries for MSSQLSvc/servername.domain.com:1433 in Active Directory.


when i ran a listing of all SPN entries. I see the server itself has the principal name listed as well as the sql administrator account.

all other talk of this error suggests removing the bad server SPN but not sure which isn't supposed to have the entry. Server or AdminAccount?

i tried rebinding to AD but that didn't resolve the errors.

any help would be great.
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Question by:deeburp
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9 Comments
 
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Expert Comment

by:Darius Ghassem
ID: 37747923
Try deleting the AdminAccount
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Author Comment

by:deeburp
ID: 37747966
delete the admin account itself or just the SPN information about the server service that is on the account?

ie this below:

dn: CN=adminaccountsql,OU=Administrators,DC=domain,DC=com
changetype: add
servicePrincipalName: MSSQLSvc/devserver.domain.com:1433
servicePrincipalName: MSSQLSvc/servername.domain.com:1433
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Expert Comment

by:Darius Ghassem
ID: 37747975
So, you are using Admin account multiple SQL servers?
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Author Comment

by:deeburp
ID: 37748001
correct we have one used on both our production and dev servers
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Expert Comment

by:Darius Ghassem
ID: 37748113
Alright try using a different account for the other SQL service that might clear the dup up
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Author Comment

by:deeburp
ID: 37748150
well we actually don't have the dev server anymore.. so perhaps i can just delete that entry from the admin account?
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Expert Comment

by:Darius Ghassem
ID: 37748152
Yeah give that a shot
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Accepted Solution

by:
snusgubben earned 500 total points
ID: 37749328
If the SQL service runs with the Network Service account, the SPN should be registered on the server object.

If the SQL service runs with a service account ("AdminAccount"), then the SPN should be registered on the user object.
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Author Closing Comment

by:deeburp
ID: 37783174
looks like this worked.. i have just the adminaccount running as the service so i've removed the spn for the server itself. so far no errors in the dc logs
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