Description
FortiOS uses 'Link Monitor' and 'Link-Monitor' for different scope.
This article describes the difference between both.
Solution
The 'Link Monitor' is monitoring the status of every interface.
It is enabled by default and it does not require any additional setting.
The log entry is 'action="interface-stat-change" status="DOWN" msg="Link monitor: Interface WAN2 was turned down' (or up).
'Link-monitor', instead, is a feature where FortiGate is a link health monitor that are used to determine the health of a single interface.
It is configured in config system link-monitor.
When 'Link-Monitor' is failing an event is registered in the FortiGate.
When 'Link-Monitor' is failing an event is registered in the FortiGate.
'Link Monitor changed state from alive to die, protocol: ping.'
If 'Link-monitor' option like 'update-static-route' is configured, this event will pop-up too.
If 'Link-monitor' is used to bring other interfaces down when link monitor fails, a 'Link Monitor' event is registered but as a result of 'Link monitor' failure.
Related document.
