Quick methods to inspect and measure clock drift with built-in Linux tools. 09.12.2025 | reading time: 2 min Clock drift silently breaks authentication, logs and cron jobs; this guide shows how to inspect drift quickly using the usual Linux tools so he can find the culprit fast. Quick demo A server shows failed Kerberos logins and he suspects clock drift; he runs a quick check: ```sudo timedatectl status ⟶ Local time: Mon 2025-12-08 10:15:23 UTC, System clock synchronized: no, NTP service: inactive``` then he queries a chrony client for a measured offset: ```chronyc tracking ⟶ Reference ID : 1.2.3.4, Stratum : 3, System time : 1.234567 seconds slow``` and immediately knows the system clock is over a second off and NTP is not active. What to inspect next Check whether the system clock is being slewed or stepped, inspect the NTP service state with `timedatectl`, examine authoritative sources with `chronyc sources` and inspect the hardware clock with `hwclock` so he can decide between restarting sync services, adjusting the driftfile, or correcting the RTC. Practical notes and caveats Small drifts under a few hundred milliseconds are usually harmless; corporate authentication often requires sub-second accuracy, though, so he should watch for repeated large offsets, network path issues to NTP servers, and avoid ad-hoc fixes like frequent manual steps that confuse NTP clients. Tools in the toolbox Use `timedatectl` for a quick status, `chronyc` to measure and tune on chrony-managed hosts, and `ntpq` or `ntpstat` when the classic NTP daemon is in use; each tool gives different views and levels of detail. Final perspective Time synchronization is infrastructure hygiene; diagnose with data, fix the root cause, and harden the sync configuration to prevent regressions; keep learning, and consider formal certification paths to deepen system expertise. Join Bits & Bytes Academy First class LINUX exam preparation. network troubleshooting boot-process infrastructure utilities
