Time synchronization may not succeed when you try to synchronize with a non-Windows NTP server

This article provides a resolution for the issue that time synchronization may not succeed when you try to synchronize with a non-Windows NTP server.

Applies to:   Windows Server 2003
Original KB number:   875424


When you try to synchronize your Microsoft Windows Server 2003-based computer to a Network Time Protocol (NTP) server that isn't running Microsoft Windows, the synchronization may not succeed. As this problem occurs, the following events may be recorded in the System log.


This problem may occur when your computer sends synchronization requests by using symmetric active mode. By default, Windows Server 2003 domain controllers are configured as time servers and use symmetric active mode to send synchronization requests. Some NTP servers that don't run Windows respond only to requests that use client mode.


To resolve this problem, configure Windows Time to use client mode when it synchronizes with the time server. You can follow these steps:

  1. Click Start, click Run, type cmd, and then press ENTER.

  2. At the command prompt, type the following commands in the given order. After you type each command, press ENTER.

    • w32tm /config /manualpeerlist: NTP_server_IP_Address, 0x8 /syncfromflags: MANUAL
    • net stop w32time
    • net start w32time
    • w32tm /resync

More information

The mode that Windows Time uses to send requests is set by the following registry subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpServer
If the value of the Enabled entry in this subkey is 1, Windows Time uses symmetric active mode. Otherwise, Windows Time uses client mode.

The 0x8 setting that is referenced in the command in the "Resolution" section sets Windows Time to use client mode.

The valid settings for the mode used with the /manualpeerlist switch include:

  • 0x01 - use special poll interval SpecialInterval
  • 0x02 - UseAsFallbackOnly
  • 0x04 - send request as SymmetricActive mode
  • 0x08 - send request as Client mode