Transparency
Colophon, hardware and sources
Connection details, hardware, accuracy budget, backup sources, configuration and honest limits — if a time server expects you to trust it, it has to publish what it does and how.
The server
everything you need to connectNTS · RFC 8915
Hardware
the physical chain that makes the timeDL20 Gen9
3.40 GHz
2133 · ECC
500 GB SSD
| Component | Model | What it does |
|---|---|---|
| GNSS receiver | Quectel LC29H · Waveshare GPS/RTK HAT | Receives GPS, GLONASS, Galileo and BeiDou on the L1 and L5 bands together. Two bands let it measure the ionospheric delay instead of estimating it. It emits one pulse at the start of every second (PPS). |
| Antenna | Active dual-band (L1 + L5), IP67 | Mounted on the front face of the building, above the air-conditioning units, with a wide view of the sky; satellites are received from every direction (visible on the live sky map). Its built-in amplifier covers the loss of the cable run. |
| Antenna cable | LMR-400, 20 m | Low-loss coaxial: about 3–4 dB over 20 metres at 1.5 GHz. It joins the antenna's own 3 m lead through a single connector; the delay of both is compensated in the accuracy budget. |
| Timestamping | Intel i210-T1 (firmware 3.25) | The PPS pulse is timestamped by the network card's own clock. The operating system is not involved, so interrupt latency never enters the measurement. |
| Network | The same i210 card · 1 Gbit/s full duplex | The card that answers NTP packets and the clock that timestamps the second are one and the same. Nothing is lost converting between two clocks. |
| Out-of-band management | HPE iLO 4 (2.40) | Power, console and hardware health even when the server is off. Reachable only from our internal network. |
The two on-board Broadcom BCM5720 ports are not used for time traffic: they support hardware timestamping for PTP packets only, not for NTP. All time traffic goes through the i210.
Accuracy budget
where the error comes from, and how much| Source | Magnitude | How it is handled |
|---|---|---|
| Antenna and cable delay | ≈ 94 ns compensated | Calculated and entered in chrony as a fixed correction: 20 m of LMR-400 ≈ 78 ns, the antenna's own 3 m lead ≈ 15 ns. Being constant, it is compensated entirely; the correction has been applied since 21 September 2026. |
| Receiver PPS error | network-verified upper bound a few ms · typically tens of ns | We cannot measure the absolute value of this term: that would need an independent atomic reference, which we do not have. Two things we can measure. Short-term noise is already inside the pulse stability figure (2–7 ns). The upper bound is our difference against eleven network sources in six countries: the differences stay within a few milliseconds and below each source's network path uncertainty (half the round trip), so almost all of it comes from the network path. For a dual-band receiver under open sky the typical value is tens of nanoseconds. Our antenna has been outdoors since 21 September 2026: 30 satellites, 40–49 dB-Hz, HDOP 1.0. |
| Hardware timestamping | 2–7 ns measured | How steadily the i210 timestamps the pulse, measured as the standard deviation of one-second intervals. |
| chrony loop | 1–4 ns measured | How tightly the system clock follows the pulse, measured as RMS offset. |
| Network path (reaching you) | 0.1–50 ms | This is the largest term and it is not ours to control. If the outbound and return paths differ, half of that difference lands directly in your clock. Clients in the same datacentre see microseconds; distant ones see milliseconds. |
Even when the server's own clock is accurate to nanoseconds, the network decides how accurate the time you receive is. That is why a geographically close server usually beats a more "precise" one further away.
Network and hosting
where it sits and how it connectsİzmir, Türkiye
Facility infrastructure: N+1 redundant generators, UPS and cooling. The fuel tank holds enough for 72 hours of operation during a grid outage. The site is watched around the clock by a network operations centre.
Hostname and address match in both directions (ntp.alastyr.com ↔ 5.2.80.90). Time traffic is exempted from connection tracking in the firewall, so no packets are dropped even under heavy pool load.
Software and monitoring
what runs, what is recorded| Layer | Version | Note |
|---|---|---|
| Operating system | AlmaLinux 10.2 · kernel 6.12 | Security updates are checked daily. |
| Time server | chrony 4.8 | Built with NTS, hardware reference clock and authenticated upstream support. |
| GNSS driver | gpsd 3.26.1 | Reads the receiver only; it never changes its settings. |
| Web server | nginx 1.26.3 | The site is fully static: no dynamic code runs on the server and there is no database. |
Backup and cross-check sources
take over if satellites are lost · our clock is compared with them continuouslyTime comes from the satellites; these eleven servers do two jobs. Our clock is compared with them continuously, and if the satellite signal is lost for 10 minutes chrony picks the ones that agree with each other and keeps the clock running on them (stratum 2). Which one is in use shows live in the "Now" column. With seven independent administrations, even if one institution were completely wrong the others would rule it out. TÜBİTAK UME is domestic and traceable to Türkiye's national time scale; in our measurements it appears about 5 ms off because of network path asymmetry — details on the measurements page.
| Institution | Country | Time scale | Protection | Now |
|---|---|---|---|---|
| TÜBİTAK UME | Türkiye | UTC(UME) — 5× caesium + 1× hydrogen maser | plain NTP | standby |
| PTB · ×3 | Germany | UTC(PTB) | NTS | standby |
| Netnod · ×2 | Sweden | stratum 1 | NTS | standby |
| INRIM · ×2 | Italy | UTC(IT) | plain NTP | standby |
| CZ.NIC | Czechia | GPS-disciplined stratum 1 | plain NTP | standby |
| RIPE NCC | Netherlands | GPS-disciplined stratum 1 | plain NTP | standby |
| Time.nl | Netherlands | GPS-disciplined stratum 1 | plain NTP | standby |
The sources were chosen by measuring them from this server with the real NTP protocol. Some candidates with attractive latency were deliberately rejected because they relay servers that apply leap smearing, such as Cloudflare.
pool.ntp.org membership
independently verifiableThis server is registered with and verified by the pool.ntp.org project,
serving the Türkiye and Europe zones. A device querying tr.pool.ntp.org may be
handed this address among the ones it receives.
The pool automatically removes servers from DNS responses if they are unreachable or more than 100 ms off. You can see this server's score and its raw measurement history below, independently — you do not have to take the claims on this page on trust.
Configuration and security posture
what is set, and why| Setting | Value | Why |
|---|---|---|
| Software | chrony 4.8 | Built with +NTS +SCFILTER +SECHASH +IPV6. |
| Minimum sources | minsources 3 | The system clock is not steered until three sources agree. |
| Maximum root distance | maxdistance 0.1 | Sources beyond 100 ms are not used. chrony's default is 3 seconds — this is thirty times stricter. |
| Poll interval | 64–512 s | The same range for every network source; at least seven samples per source per hour. |
| Sampling target | polltarget 8–12 | So the frequency estimate settles quickly. |
| Interleaved mode | xleave | RFC 9769. Requested; none of the upstream sources support it yet, and it engages by itself if support appears. |
| Source selection | real NTP measurement | Measured, not guessed; candidates relaying smearing servers were rejected. |
| Clock correction | slew only | On a running server the clock never steps; it is only sped up or slowed down. The one exception is start-up: if the clock is more than 1 second off it is corrected once within the first three updates (makestep 1.0 3). |
| Leap seconds | no smearing | The list is read locally; clients receive the standard leap indicator. |
| Mode 6/7 | none | Never implemented in chrony — there is no monlist-style reflection surface. |
| Amplification | ×1 | The reply is the same size as the request: 48 bytes. Useless for a reflection attack. |
| Rate limiting | per-client quota | A fraction of limited clients is still answered; a correctly configured client never notices. |
| Privilege isolation | seccomp -F 2 | Applied together with a systemd sandbox. |
| Management interface | local only | Unreachable from anywhere but 127.0.0.1 and ::1. |
| Web interface | fully static | No PHP, CGI or application server runs on the host. |
Honest limits
what you should knowThe limit of our redundancy: one server, one antenna, one location. If the satellite signal is lost — antenna fault, broken cable, jamming — the server switches over on its own after 10 minutes and keeps running as a stratum 2 fed by national time laboratories and independent stratum-1 servers in six countries. A watchdog service performs that switch and we publish the measured behaviour. We do not hide that switch: the current stratum and time source are published live through status.json and gnss.json. We have no atomic holdover oscillator.
On critical systems always configure several independent sources — do not depend on this server, or on any single server, alone. If you need legally traceable timestamps, approach TÜBİTAK UME's relevant services directly.
Operator
who runs this server- Company
- Alastyr Telekomünikasyon A.Ş.
- Address
- 5747 Sokak No:84, Bornova / İzmir, Türkiye
- Telephone
- +90 850 850 4678
- Contact
- hostmaster@alastyr.com — time server operations, abuse reports
- Security
- security.txt (RFC 9116)