Hello, I am resurecting this post because it seams to be the closest anyone has been to a resolution for this problem. tcpip.sys is version 5.2.3790.2709 As my trouble is to the letter the same as the first post, I would like to pick up where Charlie left off and do a trace but I am not sure how to do that; can someone explain? The output of w32tm /monitor from a client machine seems to show that all of my "BDC's" are synced to the PDC but the PDC is synced to its own internal clock: C:\>w32tm /monitor dc4.mydomain.com [172.16.2.5]: ICMP: 8ms delay. NTP: +0.0033296s offset from dc1.mydomain.com RefID: dc1.mydomain.com [10.1.1.1] dc3.mydomain.com [10.1.1.17]: ICMP: 0ms delay. NTP: -0.0384710s offset from dc1.mydomain.com RefID: dc1.mydomain.com [10.1.1.1] dc2.mydomain.com [10.1.1.23]: ICMP: 0ms delay. NTP: -0.0175720s offset from dc1.mydomain.com RefID: dc1.mydomain.com [10.1.1.1] dc1.mydomain.com *** PDC *** [10.1.1.1]: ICMP: 0ms delay. NTP: +0.0000000s offset from dc1.mydomain.com RefID: 'LOCL' [76.79.67.76] <-- shouldn't this be the IP of my time server time.mydomain.com [10.1.1.67] Thanks in advance for suggestions.