What the heck time is it?!?
summary
NTP claims to give usable time despite physics by measuring round‑trip latency to servers, cutting latency in half and slewing clocks instead of stepping except when large errors require a jump. Concrete limits: 500 parts per million slew cap, sync interval every 64 seconds, step threshold ≈ 128 milliseconds and outright reject above ~1000 seconds. It combs multiple servers, favors low‑latency replies, discards outliers, and can be inspected with tcpdump -vv port 123.
AI-written summary · about
chapters (4)
related talks
43mTic-Tac... Bomb! Master time and NTP before it's too late
27mAuthenticated Network Time Synchronization
32mYou Depend on Time, This Is How It Works and You Won’t...
15mSo what is this time thing anyway?
50mOverTime: Remote Timing Attacks Against IoT Devices
39mEverything Everywhere All at Once…in 2038
38mA Matter of Time
50mThe Time is Now: Criticality of Time Synchronization & Information Security