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Introduction

This is intended to walk you through setting up a Microsoft Windows 2003 Standard Server domain controller as an Authoritative Time Server, which synchronizes with an external time source. All members of the domain can then synchronize time with the internal Authoritative Time Server (stratum 2).

Research

It is highly suggested that you first familiarize yourself with how time servers operate. A good starting point for this is Wikipedia: Network Time Protocol, The Official US Time Website and the Time Service Department of the US Naval Observatory.

As mentioned within the Introduction, this document is designed to help configure a Stratum 2 server.

Please review the following as a good reference of available time servers:

http://tf.nist.gov/service/time-servers.html

Conventions

Within this document, we will use the following time servers:

time-b.timefreq.bldrdoc.gov
time-nw.nist.gov
nist1-dc.WiTime.net

When working with the Microsoft Windows Registry, "HKEY_LOCAL_MACHINE" will be abbreviated as "HKLM" so as to save space. Also, registry paths are will look like this: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

Items to be typed, coded, noted, or such look like this: load *,8,1

Button names and such will be bold.

Windows 2003 Server Domain Controller Configuration Instructions

• Change the server type to NTP. The default is NT5DS.
• Open Regedit. Click Start, click Run, type regedit, and then click OK.
• Locate and then click the following registry subkey:
  HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Parameters\
• In the right pane, right-click Type, and then click Modify.
• In the Edit Value dialog box, under Value data, type NTP, and then click OK.
• Declare this server as a reliable source for time. Set AnnounceFlags to 5.
• Locate and then click the following registry subkey:
  HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Config\
• In the right pane, right-click AnnounceFlags, and then click Modify.
• In the Edit DWORD Value dialog box, under Value data, type 5, and then click OK.
• Select the poll interval.
• Locate and then click the following registry subkey:
  HKLM\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient\
• In the right pane, right-click SpecialPollInterval, and then click Modify.
• In the Edit DWORD Value dialog box, under Base, click Decimal.
• In the Edit DWORD Value dialog box, under Value data, type 3600, and then click OK.

Note 3600 is the TimeInSeconds value, which is the number of seconds that you want between each poll. Microsoft recommends a value of 900 Decimal, though this may be a little excessive for most networks. This value configures the time server to poll every 15 minutes. The default setting of 3600 Decimal should suffice for most networks.

• Enable NTPServer.
• Locate and then click the following registry subkey:
  HKLM\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpServer\
• In the right pane, right-click Enabled, and then click Modify.
• In the Edit DWORD Value dialog box, under Value data, type 1, and then click OK.
• Specify the time sources. This will be a space-delimited list of stratum 1 time servers. Since we wil be using DNS names, rather than IP addresses, we need to append ",0x1" to each stratum 1 server. If you opt to use just IP addresses, you can remove the ",0x1".
• Locate and then click the following registry subkey:
  HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Parameters\NtpServer
• In the right pane, right-click NtpServer, and then click Modify.
• In Edit Value, in the Value data box, type:
  time-b.timefreq.bldrdoc.gov,0x1 time-nw.nist.gov,0x1 nist1-dc.WiTime.net,0x1
  and then click OK.
• Configure the time correction settings.
• Locate and then click the following registry subkey:
  HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Config\
• In the right pane, right-click MaxPosPhaseCorrection, and then click Modify.
• In the Edit DWORD Value dialog box, under Base, click Decimal.
• In the Edit DWORD Value dialog box, under Value data, type 3600, and then click OK.

Initially, you may want an extreme MaxPosPhaseCorrection setting to allow for very off time settings of client workstations and devices. So, for the first few days, you may want to set the MaxPosPhaseCorrection to 4294967295 Decimal or ffffffff Hexadecimal. After all devices have synchronized and show a sane time, you may want to set the MaxPosPhaseCorrection to a more reasonable TimeInSeconds value such as one hour (3600 Decimal) or 30 minutes (1800 Decimal). The value that you choose will depend on the poll interval, the network condition, and the external time source.

• Locate and then click the following registry subkey:
  HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Config\
• In the right pane, right-click MaxNegPhaseCorrection, and then click Modify.
• In the Edit DWORD Value dialog box, under Base, click Decimal.
• In the Edit DWORD Value dialog box, under Value data, type 3600, and then click OK.

Initially, you may want an extreme MaxNegPhaseCorrection setting to allow for very off time settings of client workstations and devices. So, for the first few days, you may want to set the MaxNegPhaseCorrection to 4294967295 Decimal or ffffffff Hexadecimal. After all devices have synchronized and show a sane time, you may want to set the MaxNegPhaseCorrection to a more reasonable TimeInSeconds value such as one hour (3600 Decimal) or 30 minutes (1800 Decimal). The value that you choose will depend on the poll interval, the network condition, and the external time source.

• Exit Registry Editor.
• At the command prompt, type the following command to restart the Windows Time service, and then press ENTER:

  net stop w32time && net start w32time

• Run the following command on computers other than the domain controller to reset each computer's time against the time server:

  w32tm /resync /rediscover

References

http://www.time.gov/

How to synchronize the time with the Windows Time service in Windows XP

How to configure an authoritative time server in Windows XP

How to configure an authoritative time server in Windows Server 2003

Windows Time Service and Internet Communication

Configuring the Windows Time Service

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