On a windows XP client that is a member of a domain, resetting the Windows time service to defaults (w32tm /unregister, w32tm /register) enables the NTP server on the XP machine itself.

(HKLM\System\CurrentControlSet\Services\W32Time\TimeProviders\NtpServer\Eanbled = 1)

It also says this in the MS docs on WTS registry settings here: http://technet.microsoft.com/en-us/library/cc773263(WS.10).aspx

The server shows as being enabled by doing a "netstat -a":

UDP XP-PC:ntp :


Is there any harm in disabling it?


IF the XP machine is a part of the domain, it's going to pull it's clock from the DC running the PDC Emulator anyway. I don't think there is any harm with leaving it, or changing it if you really feel the need.

  • Agreed, the XP client will get it's time from a DC, I don't get why XP needs to have it's own NTP server enabled. Seems strange to me, why enable it by default if it's pretty likely that nothing will use it. I think I'm going to disable it and see what happens. Thanks for your input :) – simon Nov 4 '10 at 19:18
  • @Simon I wouldn't recommend overriding default behavior unless you have a compelling reason to do so. That kind of approach generally leads to hassles later on, when the non-standard configuration has unintended consequences. – Chris Thorpe Nov 4 '10 at 21:08
  • @Chris: good point. I've already disabled this on a couple of test PCs right next to me... I'll post back here if something strange happens. I think I'll leave it in production though. – simon Nov 4 '10 at 21:38

Because if the computer time differs from the domain controller(s)'s time, domain login can fail.

  • I know that XP needs to stay in rough time sync with a DC. But what is the point of XP defaulting to running it's own NTP server? (I've edited my question to make it a bit more clear) – simon Nov 4 '10 at 19:07
  • @simon Interesting, I'd have expected that from joining a workgroup, not a domain. I don't know why it's doing that. – Mark Allen Nov 5 '10 at 20:19
  • Strange isn't it? I just found this which kind of implies that it is ok to disable it: technet.microsoft.com/en-us/library/cc785927(v=WS.10).aspx – simon Nov 8 '10 at 10:55

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