Description
This article describes how to control the Discovered Device Timeout for Device Monitoring. The FortiGate unit can monitor networks and gather information about the devices operating on those networks. Collected information includes:
- MAC address.
- IP address.
- Operating system.
- Hostname.
- User name.
- How long the device has been detected and on which FortiGate interface.
Devices that were automatically discovered by FortiGate will expire in 28 days by default if FortiGate does not see the device in the network anymore. In several cases, keeping the default settings (28 days) will consume the Firewall's resource (such as CPU and memory); hence reducing this value is recommended.
Scope
FortiGate.
Solution
The expiration timer can be changed using the commands below:
config system settings
set discovered-device-timeout 28 <1-365 days>
end
Variable:
discovered-device-timeout
<days_int>
Description:
Enter the timeout for discovered devices. Range:
1 to 365 days.
Default:
28
Alternatively solution or if it is preferable to clear FortiGate's unit inventory to a certain interval that is less than a day (or less than 24 hours), an auto-script can be configured for that. The steps are stated in the following KB article: Technical Tip: How to clear the unit inventory list from FortiGate in particular interval
Related articles:
Technical Tip: Enable 'Device Detection' to allow FortiOS to monitor networks
Technical Tip: How to disable the device database
