ntpsec.anastrophe.com

Attention:
This service is shut down for general clock sync. I'll still accept peering requests, but service availability isn't guaranteed. I'm no longer running dual timeservers on battery backup: no more four-nines availability (so sad).

NTP and SNTP service is available on port 123. Sorry, no IPv6 nonsense for me.
NTS service is available on port 4460. Use domain name nts.anastrophe.com.

You can verify the NTS cert here: What's my chain cert
And third-party verification of the time is here: Web Wiz NTP server test tool

ntpviz generator (this server):
- Raspberry Pi 4 Model B Rev 1.5, 4gb ram
- OS: Raspbian 11.x - Bullseye
- Webserver: NGINX
- Monitoring: Monit (highly recommended)
- Roughly 5 minutes once per hour to generate all graphs

A portion of the journey here: (outdated), and a more recent configuration (currently only one timeserver).

ADS-B - Flight Tracking For Fun And No Profit

Most of the time, only one of a-ntpsec or b-ntpsec will be 'up'. I swap one or the other in place if significant downtime is necessary for maintenance.

a-ntpsec.anastrophe.com

Refclock: uBlox Neo m8t HAT on a Raspberry Pi 3 Model B+ Rev 1.3
OS: Raspbian 11.x - Bullseye (64bit)
Time sync: gpsd 3.25 and NTPsec ntpsec-1.2.3

b-ntpsec.anastrophe.com

Refclock: Adafruit Ultimate GPS HAT on a Raspberry Pi 3 Model B+ Rev 1.3
OS: Raspbian 11.x - Bullseye (64bit)
Time sync: gpsd 3.25 and NTPsec 1.2.2a

All graphs generated with ntpviz.

Many (most?) elements shamelessly cadged from Royce Williams' most excellent NTP resource site.

This site tests "A+" on the Qualys SSL Labs Server Test page.