Time services

The service provides accurate time (in UTC scale) and serves for the synchronization of computer clock. CESNET runs several primary NTP servers (Stratum-1) whose time is synchronized with rubidium clock. The link to the UTC scale, operated by UFE AV ČR, is ensured by optical transmission, and by an independent comparison by means of GPS receiver.

Key benefits

  • We run NTP servers of own construction with stable time base. The server clock accuracy is within microseconds;
  • Own atomic time scale in the form of caesium-standard clock linked to the UTC scale;
  • The service is provided is an open mode (non-authenticated), or in an authentication mode when a time information is signed by a server key.

Target audience

The service is primarily aimed at members and other entities running own NTP servers at a lower level, or those with no time servers. At present, the service is operated as open.


The service is available to the public free of charge.


The service is publicly available at the tik.cesnet.cz and tak.cesnet.cz servers.

Related services

Last change: 23.5.2017