Time Synchronization on Linux with NTP and chrony

Accurate time synchronization matters more than most admins realize — Kerberos authentication, TLS certificate validation, and distributed systems all fail in subtle ways when clocks drift out of sync.

sudo apt install chrony

# Check sync status
chronyc tracking
chronyc sources -v

# Configure specific NTP servers
sudo nano /etc/chrony/chrony.conf
# pool time.cloudflare.com iburst

sudo systemctl restart chrony

Why chrony Replaced ntpd

chrony syncs faster after a long offline period, handles intermittent network connectivity (laptops, VMs that pause) far better than the older ntpd, and generally maintains more accurate time on typical hardware — most modern distros now ship chrony as the default NTP client instead of the historically standard ntpd.

Why This Actually Matters

Kerberos tickets (used by Active Directory authentication) are rejected if the client and server clocks differ by more than a configured tolerance (often just 5 minutes) — “authentication randomly fails” on a Linux box joined to a Windows domain is very frequently just clock drift, not a real credentials problem.