A public, GPS-referenced
stratum 1 time server, from İzmir
Accurate time from a source you can verify. Our time comes straight from the GPS, GLONASS, Galileo and BeiDou satellites: a dual-band antenna on the building, a receiver wired into the server, and a network card that timestamps the second in hardware. It is cross-checked continuously against national time laboratories and independent stratum-1 servers in six countries. Authenticated with NTS, free, no registration, reachable over both IPv4 and IPv6.
Comparing your device's clock against this server…
Live status
refreshed every 15 seconds · no dynamic code runs on the serverTraffic
since the service was last startedOur time comes from the sky
live · refreshed every 15 seconds · —The centre is straight up (İzmir), the outer circle is the horizon. Each satellite sits over the place it is directly above; the shaded area is night. Filled dots are the satellites used in the time solution.
Last 24 hours
—How one second reaches this server
- 01
Atomic clocks in orbit
Every GPS, GLONASS, Galileo and BeiDou satellite carries atomic clocks; ground stations measure them continuously and broadcast the corrections. All of them are traceable to UTC.
4 constellations - 02
Dual-band antenna
It receives the L1 and L5 bands together. Two bands let the receiver measure the ionospheric delay instead of estimating it.
L1 + L5 bands - 03
Quectel LC29H receiver
It solves position and time, then emits one electrical pulse at the start of every second (PPS). The edge of that pulse is the second.
1 pulse per second - 04
Intel i210 hardware clock
The pulse is timestamped by the network card's own clock. The operating system never gets in the way; measured stability is around 4 ns.
stamp stability 2–7 ns - 05
chrony
It locks the system clock to that pulse. If no pulse arrives for 10 minutes, the server switches to its backup on its own: time then comes from national laboratories and independent stratum-1 servers in six countries and it continues as a stratum 2. When the pulses return it locks back onto the satellites within a minute. Either way, the current source is stated in status.json.
fails over in 10 minutes - 06
The answer to you
The same card answers NTP and NTS packets. The clock that timestamps the second and the card that sends the packet are one and the same, so nothing is lost in translation. The same clock is also served signed over Roughtime, and its state is written to the time evidence log every minute.
123/udp · 4460/tcp · 2002/udp
What stratum 1 changes
time from the network versus time from the sky · numbers from this server| Aspect | Stratum 2 · time from the network | Stratum 1 · time from satellites (this server) |
|---|---|---|
| Source of time | Another time server on the internet | The atomic clocks on GPS, GLONASS, Galileo and BeiDou satellites, directly |
| Server clock accuracy | Typically 0.5–2 ms. We measured our former virtual server: ~1.8 ms behind. | Nanoseconds — measured RMS offset 1–4 ns |
| Advertised error bound | 1–20 ms (root delay + dispersion) | ~2 µs |
| Network asymmetry | Affected: half the difference between the outbound and return paths becomes error. We measured ~5 ms on the national source in Ankara. | Not affected: the time comes from the antenna, not the network |
| What it depends on | The continuity of upstream servers and the internet link | The antenna and its view of the sky. The clock stays right even if the internet link drops. |
| If the source is lost | Switches to another upstream; noticing a faulty source can take several rounds | Runs on its own clock (3 µs per hour drift), switches to network sources after 10 minutes |
| Client in the same datacentre | Milliseconds — the source's error is passed straight through | Microseconds |
| Distant client | Source error + network path error | Network path error only — the source side is close to zero |
An honest note: for a distant client, accuracy is mostly set by its own network path. The gain from stratum 1 is felt most by clients in the same city and on the same network; for distant ones, the source side of the error disappears. Stratum is not a quality grade but a distance from the reference — method and details are on the measurements page.
Backup and cross-check sources
take over if satellites are lost · 7 independent administrations · 11 servers · all stratum 1| 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 |
Time 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.
Who we serve
aggregated once a day · no individual IP address is storedSigned time and time evidence
New beyond NTP: verifiable timeRoughtime
Time from the same GPS clock with every reply signed with Ed25519 (IETF draft). A secure starting point for devices
with no clock, proof that a server lied, document timestamps. roughtime.alastyr.com:2002
Time Evidence
Every minute of our clock in a signed transparency log: GPS lock, error bound, holdover, source changes, timestamped by independent Roughtime witnesses. Verify any past moment in your browser and download the evidence bundle.
Query a moment →Quick setup
use the hostname, not the IP — then an address change cannot affect youLinux · chrony NTS · recommended
server ntp.alastyr.com iburst nts
ntsdumpdir /var/lib/chronyLinux · chrony plain NTP
server ntp.alastyr.com iburstmacOS sudo
sudo systemsetup -setnetworktimeserver ntp.alastyr.com
sudo systemsetup -setusingnetworktime onWindows administrator
w32tm /config /syncfromflags:manual ^
/manualpeerlist:"ntp.alastyr.com,0x8"
w32tm /config /update
w32tm /resyncMikroTik RouterOS 7
/system ntp client set enabled=yes
/system ntp client servers add address=ntp.alastyr.comWhat breaks when the clock drifts
the top rows show within minutes, the bottom ones stay silent for months| What is affected | Tolerance | Once the threshold is crossed |
|---|---|---|
| Kerberos / Active Directory | 5 minutes | Authentication stops entirely. Ticket freshness is bounded by this window by default. |
| TOTP / two-factor authentication | 30 seconds | Codes are rejected. Offset between the server and the phone shifts the window. |
| TLS certificates | validity window | A valid certificate is refused. A clock running fast or slow produces the same result. |
| Session and token lifetimes | absolute time | JWTs, signed cookies and cache validity break; sessions expire early or linger past their end. |
| SIEM and event correlation | event ordering | When logs from differently-set systems are merged, events appear in the wrong order. |
| Databases and replication | conflict resolution | Timestamp ordering breaks and produces silent data inconsistency. |
Read on
Setup
chrony, timesyncd, ntpd, Windows, macOS, MikroTik, Cisco, Juniper, pfSense, ESXi, Proxmox, KVM, NAS, OpenWrt, Raspberry Pi and containers — sixteen platforms.
Open → 02Verify
Measure without touching the system clock, the values to expect, and ten common problems with their causes and fixes.
Open → 03Frequently asked questions
Twenty-two questions: NTP and NTS, time from satellites, GPS time and UTC, what happens if the signal is lost; rules of use.
Open → 04Colophon
Hardware, accuracy budget, backup sources, pool.ntp.org membership and honest limits.
Open →Alastyr's other open services
same network, same terms — freeLinux mirror
Open Linux distribution mirror. Debian, Ubuntu, AlmaLinux, Rocky Linux, Linux Mint, Arch Linux, Cygwin, VideoLAN and CTAN repositories; 10 Gbps, no rate limits or quotas, over HTTP, HTTPS and rsync.
Go to service →Looking Glass
Run ping, traceroute and BGP path queries from the AS3188 network; IPv4 and IPv6 supported.
Go to service →Speed test
A free Ookla Speedtest server in İzmir, open to the community. Server ID 47198, 10 Gbps, IPv4 and IPv6.
Go to service →