Microsoft Windows 2000 and Microsoft Windows Server 2003 offer the capability of tracing detailed Kerberos events through the event log mechanism. You can use this information when you troubleshoot Kerberos. This article describes how to enable Kerberos event logging.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

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Enabling Kerberos Event Logging on a Specific Computer

1.	Start Registry Editor.
2.	Add the following registry value: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\Kerberos\Parameters Registry Value: LogLevel Value Type: REG_DWORD Value Data: 0x1 If the Parameters subkey does not exist, create it. Note Remove this registry value when it is no longer needed so that performance is not degraded on the computer. Also, you can remove this registry value to disable Kerberos event logging on a specific computer.
3.	Quit Registry Editor. The setting will become effective immediately on Windows Vista, on Windows Server 2003, and on Windows XP. For Windows 2000, you must restart the computer.

You can find any Kerberos-related events in the system log.

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Turning on Kerberos event logging is intended only for troubleshooting purpose when you expect additional information for the Kerberos client-side at a defined action timeframe.

From a general point of view, you may receive additional errors that can correctly be handled by the receiving client system without the user interference. Therefore, it does not reflect a severe problem that must be solved or even can be solved.

For example, an event log 3 about a Kerberos error that has the error code 0x7 KDC_ERR_S_PRINCIPAL_UNKNOWN for Server Name cifs/<IP address> will be logged when a share access is made against a server IP address and no server name. If this error is logged, the Windows client automatically tries to fail back to NTLM authentication for the user account. If this operation works, receive no error.

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