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. Please note that while we make every effort to ensure that the names of the servers are correct, we only control the names of the nist.gov servers. It is probably safest to use the IP addresses instead of the domain names when accessing the other servers.

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.

Because requests for NIST Internet Time Service continue to rapidly grow, we are always interested in the possibility of expanding the number of servers and broadening their geographic distribution. All organizations interested in possibly hosting a NIST Internet Time Service server are invited to contact Time and Frequency Division Chief Thomas O'Brian for more information, including a description of the equipment that the organization must have available and a discussion of the other technical qualifications necessary to host a server: obrian@boulder.nist.gov . NIST does not charge the hosting organization for this service.