Technical Tip: Importance of accurate time synchronization on FortiGate for logging, security, and troubleshooting

[ggulnaz]

Description	This article describes why accurate time synchronization on FortiGate is more than a basic configuration step and how it is foundational for reliable logging, certificate-based services, HA investigations, and Security Fabric visibility.
Scope	FortiGate.
Solution	Why accurate time matters: Logging and Event Correlation: FortiGate event, traffic, and UTM logs all depend on synchronized timestamps to reconstruct incidents accurately. Even minor time drift can break event sequencing and lead to incorrect root cause analysis, especially when logs are reviewed on FortiAnalyzer or external SIEM platforms. Time-dependent security decisions: Beyond logging, several FortiGate security features rely directly on correct system time. Certificate validation for SSL VPN, IPsec, and SSL inspection, as well as time-based authentication mechanisms and FortiGuard service validation, can fail or behave inconsistently when system time is inaccurate. These issues often appear intermittently, making them difficult to diagnose without checking the NTP status. Troubleshooting and diagnostics reliability: Although CLI outputs may show the system as 'NTP synchronized', unstable or unreachable time sources can still introduce drift over time. Verifying both synchronization status and source reliability is essential before proceeding with deeper troubleshooting. Maintaining accurate time via NTP is a simple yet essential best practice that prevents a wide range of operational and security issues on FortiGate devices.