How to Set an NTP Server Group Policy
by Ruri Ranbe, Demand Media
Windows Time Service, an implementation of Network Time Protocol, ensures that the clocks on all client workstations connected to a network are synchronized. Clients associated with an Active Directory Domain Services domain obtain date and time information from an authoritative time server, called an NTP server. Administrators can configure a standalone NTP server in Windows Server operating systems. Using Group Policy Editor, you can instruct the operating system to respond to or ignore time synchronization requests from other clients in your enterprise.
Click "Start," type "gpedit.msc" into the search box, press "Enter" and select "Group Policy Editor" from the list of results.
Double-click "Computer Configuration | Administrative Template | System | Windows Time Service."
Click "Time Provider." Double-click "Enable Windows NTP Server" from the right pane.
Select "Enabled" to respond to time synchronization queries; click "Disabled" to ignore requests.
Click "OK" to configure the group policy object.
Ref: http://www.pool.ntp.org/zone/ir
Iran Time Server — ir.pool.ntp.org
List of IP time server
he global address time.nist.gov is resolved to all of the server addresses below in a round-robin sequence to equalize the load across all of the servers.
Whether you connect to a server using the name or the IP address, it is a bad practice to “hard-code” a particular server name or address into a device so that these parameters cannot be changed by the end user if that becomes necessary at some future time.
All users should ensure that their software NEVER queries a server more frequently than once every 4 seconds. Systems that exceed this rate will be refused service. In extreme cases, systems that exceed this limit may be considered as
attempting a denial-of-service attack.
| Name | IP Address | Location | Status |
| nist1-ny.ustiming.org | 64.90.182.55 | New York City, NY | |
| nist1-nj.ustiming.org | 96.47.67.105 | Bridgewater, NJ | |
| nist1-nj2.ustiming.org | 165.193.126.229 | Weehawken, NJ | All services available |
| nist1-ny2.ustiming.org | 216.171.112.36 | New York City, NY | All services available |
| nist1-pa.ustiming.org | 206.246.122.250 | Hatfield, PA | All services available |
| time-a.nist.gov | 129.6.15.28 | NIST, Gaithersburg, Maryland | All services busy, not recommended |
| time-b.nist.gov | 129.6.15.29 | NIST, Gaithersburg, Maryland | All services busy, not recommended |
| time-c.nist.gov | 129.6.15.30 | NIST, Gaithersburg, Maryland | All services available |
| time-d.nist.gov | 2610:20:6F15:15::27 | NIST, Gaithersburg, Maryland | All services via IPV6 |
| nist1.aol-va.symmetricom.com | 64.236.96.53 | Reston, Virginia | |
| nist1-macon.macon.ga.us | 98.175.203.200 | Macon, Georgia | All services available |
| nist1-atl.ustiming.org | 64.250.177.145 | Atlanta, Georgia | |
| wolfnisttime.com | 207.223.123.18 | Birmingham, Alabama | All services available |
| nist1-chi.ustiming.org | 216.171.120.36 | Chicago, Illinois | All services available |
| nist.time.nosc.us | 96.226.242.9 | Carrollton, Texas | All services available |
| nist.expertsmi.com | 50.245.103.198 | Monroe, Michigan | ok, new ip address |
| nist.netservicesgroup.com | 64.113.32.5 | Southfield, Michigan | All services available |
| nisttime.carsoncity.k12.mi.us | 66.219.116.140 | Carson City, Michigan | All services available |
| nist1-lnk.binary.net | 216.229.0.179 | Lincoln, Nebraska | All services available |
| wwv.nist.gov | 24.56.178.140 | WWV, Fort Collins, Colorado | All services available |
| time-nist.symmetricom.com | 12.10.191.251 | Symmetricom, Boulder, Colorado | |
| time-a.timefreq.bldrdoc.gov | 132.163.4.101 | NIST, Boulder, Colorado | ntp ok; time, daytime busy |
| time-b.timefreq.bldrdoc.gov | 132.163.4.102 | NIST, Boulder, Colorado | All services busy |
| time-c.timefreq.bldrdoc.gov | 132.163.4.103 | NIST, Boulder, Colorado | ntp ok; time, daytime busy |
| time.nist.gov | global address for all servers | Multiple locations | All services available |
| utcnist.colorado.edu | 128.138.140.44 | University of Colorado, Boulder | All services available |
| utcnist2.colorado.edu | 128.138.141.172 | University of Colorado, Boulder | All services available |
| ntp-nist.ldsbc.edu | 198.60.73.8 | LDSBC, Salt Lake City, Utah | All services available |
| nist1-lv.ustiming.org | 64.250.229.100 | Las Vegas, Nevada | All services available |
| time-nw.nist.gov | 131.107.13.100 | Microsoft, Redmond, Washington | All services very busy |
| nist-time-server.eoni.com | 216.228.192.69 | La Grande, Oregon | All services available |
| nist1.symmetricom.com | 69.25.96.13 | San Jose, California | All services available |
| nist1-sj.ustiming.org | 216.171.124.36 | San Jose, California | |
| nist1-la.ustiming.org | 64.147.116.229 | Los Angeles, California | system going offline |
