Microsoft KB Archive/174557

= Time Sources Defined For The Windows NT Time Service =

Article ID: 174557

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Workstation 3.5
 * Microsoft Windows NT Workstation 3.51
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 3.5
 * Microsoft Windows NT Server 3.51
 * Microsoft Windows NT Server 4.0 Standard Edition
 * Microsoft Windows 95
 * Microsoft Network Client 3.1

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This article was previously published under Q174557



SUMMARY
There are three types of time sources that must be understood before you set up the Time Service for your computer running Windows NT.



Top Level Time Source
The top level time source represents an accurate time source such as an atomic clock. The Time Service Initialization file, Timeserv.ini, lists many different sources for accurate clocks, that is, NISTACTS, USNO, NTP, and so forth.

Primary Source (Masters of Time)
These computers get their time from a top level time source and are primary time sources for the other computers on your Local Area Network (LAN). The Type= line of the Timeserv.ini file should be set to one of the top level time sources in order to be considered a primary time source. You can have as many Primary Sources (Masters of Time) as you want on your network, but it is usually sufficient to just have one.

Type=USNO

Secondary Source
These computers have their Type= line set to Primary and the PrimarySource= line set to one (or more) of the primary sources separated by a semicolon.

Type=Primary PrimarySource=\\NTPDC1;\\NTPDC2...

The secondary sources must have their TimeSource= line set to YES. Setting the TimeSource=YES actually sets the timesource bit to true that allows down-level clients to determine who the secondary time sources are. Secondary clients issue a NetRemoteTOD API call to the primary source to get their time set.

TimeSource=YES

Clients
Computers running Windows NT can get their time from either a primary source or a secondary source. If a computer running Windows NT is to get its time from a primary source, then it sets the Type= line to Primary as explained above. However, computers running Windows NT can also get their time from a Secondary Time Source. They do this by setting their Type= line to Secondary.

Type=Secondary

By default, computers with their type set to Secondary use the NetServerEnum API call to find servers with the timesource bit set that belong to their own domain. You can specify a secondary domain with the SecondaryDomain= section of the Timeserv.ini file.

SecondaryDomain="Place the workgroup or domain name here."

For computers not running the time service, the same thing happens when they issue a NET TIME command without any paramaters (it searches its local domain for a server with its timesource bit set to YES). To get the same function as the SecondaryDomain, issue a NET TIME /DOMAIN:DOMAINNAME (secondary domain) command.

Issuing a NET TIME \\SERVER /SET /Y command will cause the down-level client to set its time with the computer specified whether it is a registered timesource or not.

NOTE: Because the clients issue a NetServerEnum to enumerate the servers with the timesource bit set to yes, it will adversely affect the Time Service if browsing is not working properly on your network.

Additional query words: timeserv time

Keywords: kbapi kbinfo kbnetwork KB174557

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