About, infrastructure and sources

Server

Time source policy

The server takes time only from stratum 1 servers; it does not connect to another stratum 2 or to a public pool. We apply three criteria when choosing sources:

• Independence: the twelve sources are spread across eight separate operators and six countries (Türkiye, Germany, Sweden, Italy, Czechia, the Netherlands).
• Diversity: some of the sources are national time laboratories that generate time from their own atomic clocks, others are satellite (GNSS) disciplined servers; the two have different failure modes.
• Verifiability: we talk to every source that supports it over NTS, with authentication (— sources).

The system clock is not updated unless at least three sources agree with each other. The current state of the sources is published on the home page.

Accuracy budget

The upper bound an NTP server can honestly state is "root delay ÷ 2 + root dispersion". The actual error is usually a small fraction of that, but because network path asymmetry cannot be determined by measurement alone, only with an independent reference, we do not promise a smaller number.

Software and monitoring

• chrony — clock discipline, NTP and NTS server. The clock is not stepped; only the frequency is corrected (except at boot).
• Status feed — chrony's own measurements are written to status.json every 15 seconds and to history.json once a minute. No dynamic code runs on the web side; the pages and data are static files.
• Certificate — the TLS certificate for NTS renews automatically; the number of days remaining is shown in the status banner.

Configuration and security posture

• Only client-mode NTP queries are answered. Management and monitoring commands are closed to the network; the server cannot be used in reflection/amplification attacks (the response size equals the request size).
• A per-address rate limit is enforced; requests over the limit are left unanswered and their share is published.
• NTS key exchange uses TLS 1.3, and cookie keys are rotated regularly.
• Leap seconds are handled the standard way; no smear is applied.

Privacy

NTP queries carry no content. Client addresses are held in memory only for rate limiting and are erased when the service restarts. For the statistics page, only totals (client count, network count, country distribution) are written to disk; individual IP addresses are not recorded. The site has no cookies, trackers or third-party scripts.

Honest limits

• Not stratum 1. We have no primary clock of our own; our accuracy is limited by the network path to the selected source.
• Virtual server. Hardware timestamping is not available; software timestamping adds tens of microseconds of jitter.
• Single location. The service is provided from a single data centre; there is no geographic redundancy. This is why we recommend configuring other sources in your client as well.
• No service level commitment. The service is provided on a best-effort basis.
• Not a legal timestamp. This service is not a substitute for a qualified timestamp or a calibration certificate.

Operator

Nerzen Bilişim Teknolojileri · AS203545 · nerzen.com. For questions about the service, abuse reports and product-embedding requests, please use the contact channels on nerzen.com.