Dictionary · Protocols and Ports
NTP
NTP — Network Time Protocol
Infrastructure · Beginner
A protocol that synchronizes clocks over the network, commonly on UDP 123. Accurate time matters for logs, certificates, and authentication tickets.
If clocks drift, log events look out of order and some logins fail because tickets look expired. Organizations point devices at trusted time sources.
Example: Domain controllers sync to an internal time source, and that source syncs to a trusted public stratum server.
Ports
- UDP 123 — Clock synchronization
Common misconception
- A few minutes of drift is not harmless in authentication. Ticket-based logins can fail or look suspicious.