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Windows components and services depend on time synchronization. For example, the Kerberos V5 authentication protocol on a Windows Server 2003 family domain has a default time synchronization threshold of five minutes (not Ten Min’). Computers that are more than five minutes out of synchronization on the domain will fail to authenticate using the Kerberos protocol. This time value is also configurable, thus allowing for smaller thresholds. Failure to authenticate using the Kerberos protocol can prevent logons, access to Web sites, file shares, printers, and other resources or services within a domain.
* Configuring time synchronization method with the following configuration commands:
w32tm.exe (Windows 2003 or XP only)
To reset to use the domain hierarchy:
w32tm.exe /config /syncfromflags:domhier
w32tm.exe /config /update
To use a specific NTP source:
w32tm.exe /config /syncfromflags:manual /manualpeerlist:source1
w32tm.exe /config /update

How to Configure an Authoritative Time Server in Windows Server 2003
http://support.microsoft.com/?id=816042

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