Network time service

Download as PDFDownload as PDF

The Janet Network Time Service delivers to Janet customers a stable time reference to organisations using the Network Time Protocol (NTP) specified in RFC 5905.

The following information is available :

  • Technical Information

For any queries, including joining the service, contact Janet Service Desk at

About the service

Janet provides five stratum-1 servers distributed across the network which peer with other time sources outside Janet.  These servers are located at:

Server location

DNS names







It is recommended that an organisation should choose between two to four local systems to be stratum-2 servers. The local server systems do not have to be reserved systems - they can do other work. However, they should be physically distributed around the organisation, so that they are not all on the same power supply or the same segment of a LAN. Each local server should be configured as a client of a Janet stratum-1 server, and as a peer to the other stratum-2s at the organisation.

Service Update - Planned Maintenance on and

Please note that the National Physical Laboratory will be carrying out some scheduled maintenance on their MSF transmission equipment which will affect the Janet NTP servers and over the dates below. There shouldn't be any interruptions to the service, but the servers ntp0 and ntp2 will be running at stratum-2 instead of stratum-1 during these maintenance periods.  For more information, please refer to the National Physical Laboratory website: The remaining Janet NTP servers should be available as normal.

•14 August - 31 August 2017 (including weekends) from 08:00 to 19:00 BST - annual maintenance period 

•14 September 2017 from 10:00 to 14:00

•14 December 2017 from 10:00 to 14:00

The shutdowns will take place between 10:00 and 14:00 UTC in December and March and between 10:00 and 14:00 BST in June and September. For the August annual shutdown period see above for timings.

The duration of each outage period will be kept to a minimum, and the signal may be back on-air prior to the times given above.

Current Service Issue:

ntp0 and ntp2 are currently running at stratum- 2