--- title: 'ntp.linuxfabrik.ch: public NTP server in the NTP Pool' url: 'https://www.linuxfabrik.ch/en/blog/public-ntp-server-ntp-linuxfabrik-ch' markdown: 'https://www.linuxfabrik.ch/en/blog/public-ntp-server-ntp-linuxfabrik-ch.md' lang: en date: '2026-10-24' description: 'ntp.linuxfabrik.ch is a public NTP server in the NTP Pool, zones ch and europe. Synchronized to seven stratum 1 sources from METAS, SWITCH, PTB and BEV.' taxonomy: category: - blog tag: - linux - news archives_month: - oct_2026 archives_year: - '2026' --- # ntp.linuxfabrik.ch: public NTP server in the NTP Pool [ Home ](https://www.linuxfabrik.ch/en) [ Blog ](https://www.linuxfabrik.ch/en/blog) ntp.linuxfabrik.ch: public NTP server in the NTP Pool `ntp.linuxfabrik.ch` is a public NTP server and part of the [NTP Pool](https://www.ntppool.org/zone/ch). Anyone may use it, directly or through `ch.pool.ntp.org` and `europe.pool.ntp.org`. ## Our own public NTP server - why? Actually, we only wanted to bring the NTP checks of the [Linuxfabrik Monitoring Plugins](https://linuxfabrik.github.io/monitoring-plugins/) up to the state of the art once again. They always worked, but there was room for more. `ntp-offset` was added, which measures the clock against any NTP server, independently of the local time service. While testing our plugins, we tripped over our own NTP configuration. [LFOps](https://linuxfabrik.github.io/lfops/), and with it many of our customer environments, had been given `ntp.metas.ch` as the time source. METAS, the Swiss Federal Institute of Metrology, operates [three public stratum 1 servers](https://www.metas.admin.ch/en/time-dissemination-via-ntp) (`ntp11`, `ntp12` and `ntp13.metas.ch`) and offers the service free of charge. chronyd polls several servers, compares their answers and steers the clock by the ones that agree - servers that are out of line get discarded. That takes at least three independent sources, as the [chrony FAQ](https://chrony-project.org/faq.html) recommends. `ntp.metas.ch`, however, is only an alias for one of these three servers. A host with this single source has nothing to compare against: if the source goes wrong, chronyd follows it without objection. The obvious alternative, `pool.ntp.org`, is ruled out as a default. The NTP Pool tells vendors who put a time server into their default configuration not to use the general pool names under any circumstances ([NTP Pool: Information for vendors](https://www.ntppool.org/vendors.html)). Instead, a vendor gets its own zone with names like `0.vendor.pool.ntp.org`, which lets the pool control the load. If you use the pool, you should support it as well. That is why we contribute a server of our own with `ntp.linuxfabrik.ch`, in the Swiss and the European zone. ## Where the time comes from A server in the NTP Pool must not use the pool as its own source. `ntp.linuxfabrik.ch` therefore synchronizes to seven fixed stratum 1 servers from four operators: - METAS, Swiss Federal Institute of Metrology: `ntp11.metas.ch`, `ntp12.metas.ch`, `ntp13.metas.ch` - SWITCH: `ntp.switch.ch` - PTB, Physikalisch-Technische Bundesanstalt (Germany): `ptbtime1.ptb.de`, `ptbtime2.ptb.de` - BEV, Bundesamt für Eich- und Vermessungswesen (Austria): `bevtime1.metrologie.at` No operator holds half of the sources. If one delivers a wrong time, the others outvote it, even if all three METAS servers are off at the same time. ## How to use it The easiest way is the pool. The distributions configure it out of the box, Rocky Linux for example with `pool 2.rocky.pool.ntp.org iburst`, Debian with `pool 2.debian.pool.ntp.org iburst`. If you leave that as it is, you are well served. If you configure a pool yourself, `2.pool.ntp.org` is the best choice. The pool then picks servers nearby, and the `2.` prefix returns IPv6 addresses as well. In `/etc/chrony.conf`: ``` pool 2.pool.ntp.org iburst ``` chronyd takes four servers from the pool and compares them with each other. `ntp.linuxfabrik.ch` may be among them by chance. If you want to use `ntp.linuxfabrik.ch` directly, add it in addition to the pool, never as the only source: ``` pool 2.pool.ntp.org iburst server ntp.linuxfabrik.ch iburst ``` Test without touching the running configuration: ``` $ chronyd -Q -t 10 'server ntp.linuxfabrik.ch iburst' ``` `System clock wrong by ...` means the server is reachable, `Timeout reached` means UDP 123 is blocked. ## We help you Need help with time synchronization or chrony? Have a look at our [Service & Support plans](https://www.linuxfabrik.ch/en/services/service-support) and [get in touch](https://www.linuxfabrik.ch/en/contact). 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