NIST Internet Time Servers

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NIST Internet Time Servers 
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  Return to NIST Internet Time Service Page   
The table below lists the time servers used by the NIST Internet Time Service (ITS). The table lists each server's name, IP address, and location, organized geographically within the US from North to South and then from East to West. Please note that while we make every effort to ensure that the names of the servers are correct, we control the names of only the nist.gov servers. If you have difficulty using the name of a system, you can access a server using the IP address directly.
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.uccaribe.edu  200.50.25.62  Bayamon, Puerto Rico  Ok  
nist1-ny.WiTime.net  64.90.182.55  New York City, NY  Recommended for new users, new domain=ustiming.org, new ip=208.184.49.9  
time-a.nist.gov  129.6.15.28  NIST, Gaithersburg, Maryland  Ok  
time-b.nist.gov  129.6.15.29  NIST, Gaithersburg, Maryland  Ok  
nist1-dc.WiTime.net  206.246.118.250  Alexandria, Virginia  Recommended for new users, new domain=ustiming.org, new ip=206.246.118.250  
nist1.aol-va.symmetricom.com  64.236.96.53  Reston, Virginia  Recommended for new users  
nist1.columbiacountyga.gov  68.216.79.113  Columbia County, Georgia  Recommended for new users  
nist.expertsmi.com  99.150.184.201  Monroe, Michigan  Recommended for new users  
nist.netservicesgroup.com  64.113.32.5  Southfield, Michigan  Recommended for new users  
time-a.timefreq.bldrdoc.gov  132.163.4.101  NIST, Boulder, Colorado  Ok  
time-b.timefreq.bldrdoc.gov  132.163.4.102  NIST, Boulder, Colorado  Very busy  
time-c.timefreq.bldrdoc.gov  132.163.4.103  NIST, Boulder, Colorado  Ok  
time.nist.gov  192.43.244.18  NCAR, Boulder, Colorado  Ok  
utcnist.colorado.edu  128.138.140.44  University of Colorado, Boulder  ok  
utcnist2.colorado.edu  128.138.188.172  University of Colorado, Boulder  Recommended for new users  
ntp-nist.ldsbc.edu  198.60.73.8  LDSBC, Salt Lake City, Utah  Recommended for new users  
time-nw.nist.gov  131.107.13.100  Microsoft, Redmond, Washington  ok  
nist1.aol-ca.symmetricom.com  207.200.81.113  Mountain View, California  Recommended for new users  
nist1.symmetricom.com  69.25.96.13  San Jose, California  Recommended for new users  
nist1-sj.WiTime.net  64.125.78.85  San Jose, California  Recommended for new users, new domain=ustiming.org, new ip=64.125.78.85  
nist1-la.WiTime.net  64.147.116.229  Los Angeles, California  Recommended for new users, new domain= ustiming.org  
The following server supports only authenticated NTP requests using the symmetric key encryption method that is defined in the NTP documentation. It does not respond to requests for time in the DAYTIME or TIME formats and will not accept anonymous ftp connections. You must apply to NIST for an encryption key to use this system; it will not respond to NTP requests from users who have not registered with NIST. This service is currently being offered on a trial basis only. See the authenticated NTP description for more information.
http://tf.nist.gov/tf-cgi/servers.cgi#
               
               
               
               

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