Definition
FortiGate Link Monitor probes network targets to detect path loss or degradation.
How it works
Probes operate with configured protocols, intervals and thresholds. Depending on version and settings, monitoring can influence routing decisions.
Real-world example
With two Internet uplinks, probing external targets can detect a broken upstream path even while the local gateway still replies.
Limits and best practices
Choose robust probe targets, avoid overly aggressive thresholds and verify interactions with SD-WAN and static routing.
Technical detail to remember
A gateway may reply to pings even when upstream Internet access has failed. Link Monitor probes should test suitable destinations beyond the local router, with thresholds that avoid unstable route changes.