The Kerberos Client Received A KRB_AP_ERR_MODIFIED Error From The Server

IT Support Forum Forums Windows Windows 10 Troubleshooting The Kerberos Client Received A KRB_AP_ERR_MODIFIED Error From The Server

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    • #2479

      I got the following error in the event log:

      * Source: Microsoft-Windows-Security-Kerberos
      * Event Log: System
      * Type: Error
      * Event ID: 4
      * Event User: N/A
      * The Kerberos client received a KRB_AP_ERR_MODIFIED error from the server xbofur$. The target name used was cifs/BOFUR. This indicates that the target server failed to decrypt the ticket provided by the client. This can occur when the target server principal name (SPN) is registered on an account other than the account the target service is using. Ensure that the target SPN is only registered on the account used by the server. This error can also happen if the target service account password is different than what is configured on the Kerberos Key Distribution Center for that target service. Ensure that the service on the server and the KDC are both configured to use the same password. If the server name is not fully qualified, and the target domain (GIS.LOCAL) is different from the client domain (GIS.LOCAL), check if there are identically named server accounts in these two domains, or use the fully-qualified name to identify the server.

      Microsoft says the cause is one of these:

      – Mismatch DNS name resolution. The issue is common in an NLB environment that uses multiple IPs or network adapters.
      – The user doesn’t have a Local NTFS access permission.
      – The Web Site is using Application Pool with a poor permission setting.

      And that the fix might be one of these:

      -Verify that the IIS has been set up with correct NTFS settings.
      -Integrated Windows Authentication (IIS 6.0)
      -Verify that each cluster node has been set up with correct DNS settings.
      -Verify that the node has been set up with correct Application Pool settings:
      -Configuring Application Pool Identity with IIS 6.0 (IIS 6.0)
      -Verify that internet explorer has been set up with a correct security setting.

      Personally, I found that (as the computer was a restored version of another computer, albeit renamed), the IP address was the same as the old IP in DNS. I deleted the server’s DNS record and registered a new DNS record and the problem seemed to go away.

    • #2486

      Today I had the Kerberos client received a KRB_AP_ERR_MODIFIED error from the server issue again with a different computer. Sure enough, I logged onto the DNS server and there were two A records with different computer names but the same IP address. I guess this might be related, given my previous experience listed in the post above, so I deleted the record with the matching IP address. Hopefully that fixes it. I’ll update this post or add a new one if the problem comes back.

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