Setting NTP in XP

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry entry:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config\
3. In the right pane, right-click AnnounceFlags, and then click Modify.
4. In the Edit DWORD Value dialog box, type 5 under Value data, and then click OK.
5. Enable NTPServer.
   1. Locate and then click the following registry subkey:
      HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpServer\
   2. In the right pane, right-click Enabled, and then click Modify.
   3. In the Edit DWORD Value dialog box, type 1 under Value data, and then click OK.
6. Exit Registry Editor.
7. At the command prompt, type the following command to restart the Windows Time service, and then press Enter:
   net stop w32time && net start w32time
8. To reset the local computers' time against the time server, run the following command on all the computers except the time server:
   w32tm /resync /rediscover

    

   To configure the Windows Time service to synchronize with an external time source yourself, follow these steps:

   1. Change the server type to NTP. To do this, follow these steps:
      1. Click Start, click Run, type regedit, and then click OK.
      2. Locate and then click the following registry subkey:
         HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Parameters\
      3. In the right pane, right-click Type, and then click Modify.
      4. In the Edit Value dialog box, under Value data, type NTP, and then click OK.
   2. Set AnnounceFlags to 5. To do this, follow these steps:
      1. Locate and then click the following registry subkey:
         HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config\
      2. In the right pane, right-click AnnounceFlags, and then click Modify.
      3. In the Edit DWORD Value dialog box, type 5 under Value data, and then click OK.
         
         Notes
         • If an authoritative time server that is configured to use an AnnounceFlag value of 0x5 does not synchronize with an upstream time server, a client server may not correctly synchronize with the authoritative time server when the time synchronization between the authoritative time server and the upstream time server resumes. Therefore, if you have a poor network connection or other concerns that may cause time synchronization failure of the authoritative server to an upstream server, set the AnnounceFlag value to 0xA instead of to 0x5.
         • If an authoritative time server that is configured to use an AnnounceFlag value of 0x5 and to synchronize with an upstream time server at a fixed interval that is specified in SpecialPollInterval, a client server may not correctly synchronize with the authoritative time server after the authoritative time server restarts. Therefore, if you configure your authoritative time server to synchronize with an upstream NTP server at a fixed interval that is specified in SpecialPollInterval, set the AnnounceFlag value to 0xA instead of 0x5.
   3. Select the poll interval. To do this, follow these steps:
      1. Locate and then click the following registry subkey:
         HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient\
      2. In the right pane, right-click SpecialPollInterval, and then click Modify.
      3. In the Edit DWORD Value dialog box, type TimeInSeconds, under Value data, and then click OK.
         
         Note TimeInSeconds is a placeholder for the number of seconds that you want between each poll. A recommended value is 900 decimal. This value configures the time server to poll every 15 minutes.
   4. Enable NTPServer. To do this, follow these steps:
      1. Locate and then click the following registry subkey:
         HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpServer\
      2. In the right pane, right-click Enabled, and then click Modify.
      3. In the Edit DWORD Value dialog box, type 1 under Value data, and then click OK.

   5. Specify the time sources. To do this, follow these steps:
      1. Locate and then click the following registry subkey:
         HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Parameters
      2. In the right pane, right-click NtpServer, and then click Modify.
      3. In Edit Value, type Peers in the Value data box, and then click OK.
   6. Configure the time correction settings. To do this, follow these steps:
      1. Locate and then click the following registry subkey:
         HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config\
      2. In the right pane, right-click MaxPosPhaseCorrection, and then click Modify.
      3. In the Edit DWORD Value dialog box, click Decimal under Base.
      4. In the Edit DWORD Value dialog box, type TimeInSecondsunder Value data, and then click OK.
         
         Note TimeInSeconds is a placeholder for a reasonable value, such as one hour (3600) or 30 minutes (1800). The value that you choose depends on the poll interval, the network condition, and the external time source.
      5. Locate and then click the following registry subkey:
         HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config\
      6. In the right pane, right-click MaxNegPhaseCorrection, and then click Modify.
      7. In the Edit DWORD Value dialog box, click Decimal under Base.
      8. In the Edit DWORD Value dialog box, type TimeInSeconds under Value data, and then click OK.
         
         Note TimeInSeconds is a placeholder for a reasonable value, such as one hour (3600) or 30 minutes (1800). The value that you choose depends on the poll interval, the network condition, and the external time source.
   7. Exit Registry Editor.
   8. At the command prompt, type the following command to restart the Windows Time service, and then press Enter:
      net stop w32time && net start w32time
   9. Run the following command on computers other than the domain controller to reset each computer's time against the time server:
      w32tm /resync /rediscover

   For more information about the w32tm command, run the following command from a command prompt:

   w32tm /?

   
   
   Note SNTP uses User Datagram Protocol (UDP) port 123. If this port is not open to the Internet, you cannot synchronize your server to Internet SNTP servers.