FortiManager supports network operations use cases for centralized management, best practices compliance, and workflow automation to provide better protection against breaches.
Article Id 279123
Description This article describes how to re-establish the FortiGate-FortiManager connectivity post uploading a new license file on FortiManager
Scope FortiManager.
  1. When the FortiGate has been onboarded into FortiManager, the FortiManager’s Serial Number will be recognized and displayed on the FortiGate’s central-management CLI:

1. FMG SN on FortiGate.png


2. FMG SN.png


  1. Verify the connection is Connected/UP on the FortiGate and FortiManager.


3. FGT.png


4. FMG.png


  1. Each license file is linked to a unique FortiManager Serial Number. Hence, if a new license file is uploaded into FortiManager, the device’s Serial Number will change and will affect the connectivity between FortiManager and FortiGate.


5. FMG new SN.png


6. FGT Connection down.png


  1. This is because the FortiManager’s Serial Number has been changed to FMG-VMXXXXXX2724 but the FortiGate is still recognizing the old Serial Number.


1. FMG SN on FortiGate.png


  1. To rectify this, navigate to Device Manager -> 'Right-click' the FortiGate -> Edit -> Re-key the admin password -> OK -> 'Right-click' the FortiGate again -> Refresh Device. After that, verify that FortiManager is able to successfully update the device information and check on the FortiGate side if the new FortiManager Serial Number is being reflected.


7. Refresh update deviec successful.png


8. Device is now up.png



9. New SN on FGT.png


  1. Alternatively, login to FortiGate and manually register the new Serial Number as follows:


FGT# execute central-mgmt register-device <FMG Serial Number> fortinet  <----- Register the new Serial Number.
FGT# fnsysctl killall fgfmd  <----- Restarts the FGFM tunnel.
FGT# diag fdsm central-mgmt status  <----- Check the connection and registration status.


Related article:

Technical Tip: How to register a FortiGate to a FortiManager from CLI