Apple runs a fleet of stratum 1 NTP servers at time.apple.com. In my experience, ntpd/chronyd are very happy with them.
It looks like, instead of doing anycast, they maybe use DNS to steer you to the closest one.
time.apple.com is a CNAME for time-osx.g.aaplimg.com. Querying a handful of DNS servers, I've identified the following locations:
| IP | Hostname | Location |
|---|---|---|
| 17.253.2.125 | usdal4-ntp-001.aaplimg.com. | Dallas |
| 17.253.2.253 | usdal4-ntp-002.aaplimg.com. | Dallas |
| 17.253.4.125 | ussjc2-ntp-001.aaplimg.com. | San Jose |
| 17.253.4.253 | ussjc2-ntp-002.aaplimg.com. | San Jose |
| 17.253.6.125 | usatl4-ntp-001.aaplimg.com. | Atlanta |
| 17.253.6.253 | usatl4-ntp-002.aaplimg.com. | Atlanta |
| 17.253.12.125 | usmia1-ntp-001.aaplimg.com. | Miami |
| 17.253.12.253 | usmia1-ntp-002.aaplimg.com. | Miami |
| 17.253.14.123 | usnyc3-ntp-003.aaplimg.com. | NYC |
| 17.253.14.125 | usnyc3-ntp-001.aaplimg.com. | NYC |
| 17.253.14.251 | usnyc3-ntp-004.aaplimg.com. | NYC |
| 17.253.14.253 | usnyc3-ntp-002.aaplimg.com. | NYC |
| 17.253.16.125 | usscz2-ntp-001.aaplimg.com. | Santa Cruz? |
| 17.253.16.253 | usscz2-ntp-002.aaplimg.com. | Santa Cruz? |
| 17.253.18.125 | brsao4-ntp-001.aaplimg.com. | São Paulo |
| 17.253.18.253 | brsao4-ntp-002.aaplimg.com. | São Paulo |
| 17.253.20.125 | usqas2-ntp-001.aaplimg.com. | Ashburn, VA |
| 17.253.20.253 | usqas2-ntp-002.aaplimg.com. | Ashburn, VA |
| 17.253.24.125 | uschi5-ntp-001.aaplimg.com. | Chicago |
| 17.253.24.253 | uschi5-ntp-002.aaplimg.com. | Chicago |
| 17.253.26.125 | uslax1-ntp-001.aaplimg.com. | Los Angeles |
| 17.253.26.253 | uslax1-ntp-002.aaplimg.com. | Los Angeles |
| 17.253.28.125 | usmes1-ntp-001.aaplimg.com. | Mesa, Arizona |
| 17.253.28.253 | usmes1-ntp-002.aaplimg.com. | Mesa, Arizona |
| 17.253.30.125 | ussea4-ntp-001.aaplimg.com. | Seattle |
| 17.253.30.253 | ussea4-ntp-002.aaplimg.com. | Seattle |
| 17.253.34.123 | uklon5-ntp-003.aaplimg.com. | London |
| 17.253.34.125 | uklon5-ntp-001.aaplimg.com. | London |
| 17.253.34.251 | uklon5-ntp-004.aaplimg.com. | London |
| 17.253.34.253 | uklon5-ntp-002.aaplimg.com. | London |
| 17.253.38.125 | sesto4-ntp-001.aaplimg.com. | Stockholm |
| 17.253.38.253 | sesto4-ntp-002.aaplimg.com. | Stockholm |
| 17.253.52.125 | nlams2-ntp-001.aaplimg.com. | Amsterdam |
| 17.253.52.253 | nlams2-ntp-002.aaplimg.com. | Amsterdam |
| 17.253.54.123 | defra1-ntp-003.aaplimg.com. | Frankfurt |
| 17.253.54.125 | defra1-ntp-001.aaplimg.com. | Frankfurt |
| 17.253.54.251 | defra1-ntp-004.aaplimg.com. | Frankfurt |
| 17.253.54.253 | defra1-ntp-002.aaplimg.com. | Frankfurt |
| 17.253.66.125 | ausyd2-ntp-001.aaplimg.com. | Sydney |
| 17.253.66.253 | ausyd2-ntp-002.aaplimg.com. | Sydney |
| 17.253.68.123 | jptyo5-ntp-003.aaplimg.com. | Tokyo |
| 17.253.68.125 | jptyo5-ntp-001.aaplimg.com. | Tokyo |
| 17.253.68.251 | jptyo5-ntp-004.aaplimg.com. | Tokyo |
| 17.253.68.253 | jptyo5-ntp-002.aaplimg.com. | Tokyo |
| 17.253.74.125 | jposa3-ntp-001.aaplimg.com. | Osaka, Japan |
| 17.253.74.253 | jposa3-ntp-002.aaplimg.com. | Osaka, Japan |
| 17.253.82.125 | sgsin3-ntp-001.aaplimg.com. | Singapore |
| 17.253.82.253 | sgsin3-ntp-002.aaplimg.com. | Singapore |
| 17.253.84.123 | hkhkg1-ntp-003.aaplimg.com. | Hong Kong |
| 17.253.84.125 | hkhkg1-ntp-001.aaplimg.com. | Hong Kong |
| 17.253.84.251 | hkhkg1-ntp-004.aaplimg.com. | Hong Kong |
| 17.253.84.253 | hkhkg1-ntp-002.aaplimg.com. | Hong Kong |
| 17.253.106.125 | dkblp1-ntp-001.aaplimg.com. | Denmark |
| 17.253.106.253 | dkblp1-ntp-002.aaplimg.com. | Denmark |
| 17.253.108.125 | frcch1-ntp-001.aaplimg.com. | France |
| 17.253.108.253 | frcch1-ntp-002.aaplimg.com. | France |
| 17.253.110.125 | zaisd1-ntp-001.aaplimg.com. | South Africa |
| 17.253.110.253 | zaisd1-ntp-002.aaplimg.com. | South Africa |
| 17.253.114.125 | krsel6-ntp-001.aaplimg.com. | Seoul, Korea |
| 17.253.114.253 | krsel6-ntp-002.aaplimg.com. | Seoul, Korea |
| 17.253.116.125 | twtpe2-ntp-001.aaplimg.com. | Taipei |
| 17.253.116.253 | twtpe2-ntp-002.aaplimg.com. | Taipei |
| 17.253.122.125 | rumow2-ntp-001.aaplimg.com. | Moscow |
| 17.253.122.253 | rumow2-ntp-002.aaplimg.com. | Moscow |
It's worth noting that this list changes over time, and you're generally probably best off using
pool time.apple.comrather than trying to rely on this maybe-outdated list. It seems like there's periodic IP renumbering that goes on too.That said, looking at IP patterns, you can kind of enumerate them like so:
Interesting (but not shocking) to note that Moscow has disappeared.
While many of these are stratum 1, there are some stratum 2 servers mixed in.