If you’re not sure how the billions of devices keep the time, you’ll be interested to know that I’m one of those timekeepers. Planet Earth has few authoritative time sources that are all in perfect sync, and the clock that we all agree on propagates from those. We call those “stratum-0” sources. The most accessible of which, is the GPS+PPS signal. The PPS (pulse per second) is a radio “tick tock” – a 1Hz square wave that is accurate to the nanosecond.
I briefly mentioned in my blog about my home network build that I hooked up a GPS+PPS receiver to serve the time with stratum-1 precision. My rig has been enrolled in the NTP Pool Project for several years now. At time of writing, there are around 80 of these servers in the AU (Australia) pool.
There’s actually less of us than that. When querying the pool, I’ve found that a decent number of them are overseas. The complete list of servers isn’t published, but you can get 4 random entries from the pool each time you make a DNS query.
$ host au.pool.ntp.org
au.pool.ntp.org has address 162.159.200.123
au.pool.ntp.org has address 159.196.3.239
au.pool.ntp.org has address 27.124.125.251
au.pool.ntp.org has address 103.126.53.123
$ host 162.159.200.123
123.200.159.162.in-addr.arpa domain name pointer time.cloudflare.com.
There’s a diverse mix of sources. Many are run by the heavyweights (CloudFlare, Amazon, Telstra). Some are run by IT consulting firms. I even found one that was run by a Grammar School in Perth.
It’s the privately run time servers that seem to be the most interesting. Many of these IP addresses resolve to single-person domains over reverse DNS. I found one that was run by a YouTuber who makes Christian music, and one who blogs about NTP and IPv6, one who blogs about their house build, MythTV and network/linux setups.
It’s amusing that we’re all into the same stuff (well, not Christian music, but I do have a YouTube channel). I did an ASD screening test not long ago, and one of the ~40 questions asked if I was fascinated by dates. It seemed like an oddly-specific question. I know the ISO8601 standard by rote, I know how timezones work and can list all the little edge cases. I feel naked without my Casio F-105W wrist watch. And yeah, I own and operate a time server on the public internet.
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