NTP (Network Time Protocol) and PTP (Precision Time Protocol) synchronize system clocks across networks. NTP typically achieves millisecond accuracy, while PTP reaches microsecond to nanosecond precision. Consistent timestamps are essential for information security: log correlation, forensic analysis, and compliance with reporting deadlines all depend on accurate time. ISO 27001 Annex A.8.17 requires clock synchronization. You should synchronize all systems against trusted time sources and document the NTP configuration in your hardening standard.