Network time service

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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 help@jisc.ac.uk

About the service

The Jisc Network Time service consists of seven 'Stratum 1' time servers separated geographically over the country:
 

Server location

DNS names

South East

ntp0.ja.net

North West

ntp1.ja.net

North West

ntp2.ja.net

North East

ntp3.ja.net

South

ntp4.ja.net

South East

ntp5.ja.net 

South

ntp6.ja.net

* Please note: While we show the geographical locations of our servers, they are all available for use nationally.

Our service uses rate limiting, if you have over ten LAN clients that require time synchronisation, we would recommend using a local time server infrastructure to serve those LAN clients and ensure a consistent service.

Our current infrastructure recommendation is to run a minimum of two network time servers.  Configuring each to use three of our servers, two common and one different, this provides a balance of consistency and resilience.

e.g.

timeserver 1 - ntp0.ja.net, ntp1.ja.net, ntp3.ja.net

timeserver 2 - ntp0.ja.net, ntp1.ja.net, ntp4.ja.net

Service updates

Planned maintenance on ntp0.ja.net and ntp2.ja.net

Please note that from time to time the National Physical Laboratory carries out scheduled maintenance on their MSF transmission equipment which will affect the Janet NTP servers ntp0.ja.net and ntp2.ja.net. Any known maintenance dates are provided 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: http://www.npl.co.uk/science-technology/time-frequency/products-and-services/time/msf-outages. The remaining Janet NTP servers should be available as normal unless other maintenance work is being carried out.

Scheduled maintenance by National Physical Laboratory:

12 June 2025 from 11:00 to 15:00 BST (UTC + 1 hour)

11 September 2025 from 11:00 to 15:00 BST (UTC + 1 hour)

11 December 2025 from 10:00 to 14:00 UTC

Additional maintenance periods:

In addition, the MSF signal will be off-air to allow the masts and antennas to be worked on safely during the period: 

Monday 21 July  to Friday 8 August 2025 including weekends, from 08:00 to 18:00 BST (UTC + 1 hour) each day.

The service will be restored overnight and at weekends whenever possible. If the weather is unsuitable for work to be carried out, then the service will not be turned off.

Current Service Issue:

none