The Network Time Protocol (NTP) is a mechanism for synchronising the time on computers. When the full NTP implementation is used, it is capable of maintaining the same time on two computers with an accuracy of around 1 ms - 30 ms despite the varying delays in internet propagation.
Further information about NTP can be obtained from the main NTP website at http://www.ntp.org/(external link)
MSL operates a pool of stratum 1 servers with the name pool.msltime.measurement.govt.nz and address 220.127.116.11.
Access to individual servers in the pool is managed by a load-balancer running on our corporate IT infrastructure. The servers in the pool are managed by Measurement Standards Laboratory. Using a pool ensures NTP clients should always be able to obtain an NTP server, with a fixed IP address, while allowing Time Standards staff to take individual servers offline if necessary.
The MSL NTP servers are synchronised using a 1 pulse per second signal to the New Zealand Time Standard. The server time is typically stable with respect to the time in the caesium clocks to around 1 microsecond, but the variability in the network delays limits the accuracy for remote clocks/clients.
The servers are publicly available to all connections from within NZ. But please note, these servers only respond to NTP and "Simple Network Time Protocol” (SNTP) requests. They do not respond to "datetime" requests.
MSL's Stratum 1 NTP servers are currently open-access but serious users, those for whom time is important, are encouraged to register their use by sending the (static) IP address of their server(s) and a contact email address to email@example.com in case we need to restrict access in the future. Please limit access to three servers and make any additional connections to what will be stratum 2 servers.
Please contact us if you have any queries about this service.