Huh. Now that I have #otel traces on a bunch of things at home, it's pretty clear that my clocks aren't in sync on every system. They're maybe 1ms off, but it's enough that supposedly-nested trace spans aren't quite nested right.

Which is annoying since I have two local GPS #NTP receivers.

The two "bad" machines were using #systemd-timesyncd to talk to Ubuntu's pool clocks instead of the local clocks. The "good" machines are using #chrony and claim that they're ~2 us off of GPS time.

Now I'm curious -- is this a problem with network latency and Ubuntu's pool, or is that just as good as timesyncd gets?

Thank you so much David Mills. #NTP

From: @jjcelery
https://mastodon.ie/@jjcelery/114248753712553115

Let's take a moment to remember the guy who made sure we don't have to change Every Goddamn Clock today, David L. Mills, creator of Network Time Protocol (NTP) who passed last year.

My wristwatch is synced to my phone, which is synced to the internet, which knows that time it is right now thanks to David Mills. Cheers to his memory

https://cse.engin.umich.edu/stories/remembering-alum-david-mills-who-brought-the-internet-into-perfect-time//

Ein Ofen, der kein #ntp beherrscht, sollte keine #Uhr haben dürfen. #zeitumstellung

Hello, fediverse friends. I have been working on my time server, time.lettersblogatory.com, for several months and have gotten it in pretty good shape. It is now ready for primetime, I hope. If you have an NTP client and would like to give it a try, please add time.lettersblogatory.com to your list of time servers. Bonus: the server is NTS-enabled! It's located in the Netherlands and is a stratum 2 server.

Just like DNS way, way, waaaaaaaay too many seem to mess up NTP. So I wrote a thing about monitoring NTP with OpenSearch/ElasticSearch.

https://www.infosecworrier.dk/blog/2025/03/ntpmonitoring/

So, quick bit of advice: if you purchase an NTP server, make sure you actually use it on things like DNS. Evidently both name servers were like 20 minutes off and none of the TXT entries were being successfully added. #homelab #dns #ntp

Did you know chrony, the #NTP implementation, sets up an administrative listener on the loopback interface using UDP/323 by default?

Unfortunately in the #RPKI rpki-rtr has TCP/323 registered with IANA (see IETF RFC 6810). UDP/323 is reserved. Reserving a transport that is unused by the assigned application is common practice these days.

chrony's choice can probably be chalked up to a historical accident since it came first and presumably picked 323 because it "looked" like 123 and was then unassigned.

Chrony should probably change their default imo, but maybe it's too late or not worth it now?

Since 18th February, my #ESP8266 chips have trouble with #NTP time via network. They do ask, the server does answer (and Linux does use these responses) – but the esp time is set to e.g. 7200 seconds (epoch), instead of 1.7 billion something.

Also, after about 20 to 30 minutes (not really periodic), they restart network, and set epoch back to 7200 seconds.

Any ideas?

Habe mal wieder ein neues Nerd-Projekt: Ein eigener Stratum 1 NTP-Zeitserver. Warum? Weil es geht. Die Daten kommen per GPS und haben dadurch eine Genauigkeit im Bereich von Nano-Sekunden. Der Testaufbau läuft, jetzt muss ich nur noch ein passendes Gehäuse drucken und eventuell die Antenne noch draußen positionieren.

I pressed the #turbo button on my laptop.

(edited for clarity)

$ sudo hwclock && date && sleep 60 && sudo hwclock && date

22:50:48.433491+01:00
02:29:53 CET 2025

22:51:44.397740+01:00
02:30:54 CET 2025

It can now finish a minue in 56 seconds!

Was scratching my head for days why my core NTP server, which is also the internally authoritative DNS provider, couldn't resolve hostnames from its ntp.conf on startup, only literal IP addresses.

Not actually listing it in its own resolver configuration, might just possibly have been at the root of it.

D'oh!

#ThrowbackThursday In 2010 I listed the frequency distribution by major version of #junos routers running in-the-wild. No one had done this before, and I was asked how I was able to do it. At the time I refused to say. Enough time has passed...

A year earlier I had begun surveying the Internet for open #NTP servers after discovering the reflection/amplification threat present in the protocol, but still not publicly disclosed. One of the things I was collecting was mode 6 control readlist responses. The system variable contains OS detail, including version info (although cisco boxes just return "cisco" :-). There were lots of Juniper routers with an open NTP listener in those days. For awhile it was a good way to see what my fellow netops were running.

My newest topic I am trying to understand better: #GNSS

While trying to write about #NTP as well as #PTP another world opened up as well. Global Navigation Satellite System or #GNSS which is most often the source of time. Digging through the different Satellite constellations #GPS , #GALILEO , #BAIDU , #GLONASS and understanding the differences was interesting.

I am still digging deeper. Anyone with knowledge, is highly welcome to educate me.

LED Wall Clock Gets Raspberry Pi Pico Upgrade https://hackaday.com/2025/01/01/led-wall-clock-gets-raspberry-pi-pico-upgrade/ #Microcontrollers #sevensegmentLED #clockhacks #PiPicoW #KiCAD #ntp

LED Wall Clock Gets Raspberry Pi Pico Upgrade - When [Rodrigo Feliciano] realized that the reason his seven-segment LED wall clock... - https://hackaday.com/2025/01/01/led-wall-clock-gets-raspberry-pi-pico-upgrade/ #microcontrollers #sevensegmentled #clockhacks #pipicow #kicad #ntp