Skip to main content
farhanahmed
Staff
farhanahmed
Staff
December 27, 2024

Troubleshooting Tip: Install failed due to vlanid already in use in device by interface

  • December 27, 2024
  • 0 replies
  • 1285 views
Description

This article describes how to troubleshoot when installing the config to a device fails with the erro: 'invalid value - prop[system interface]: vlanid <id> already in use in device by <interface>'
Scope FortiManager.
Solution
  • Verify that the VLAN ID giving the error does not already exist on the FortiGate.
  • If FortiSwitch Manager or System Templates or CLI Templates are used to create VLAN interfaces, make sure VLAN IDs are not re-used.
  • In case FortiSwitches are being used with the FortiGate and the error is for the default VLANs (VLAN-ID: 1, 4088, 4089, 4090, 4091.4092.4093) and go to the device database i.e. Device Manager -> Device & Groups, select the device -> Network -> Interface, select the Interface it gave an error for (VLAN) -> Advance options and make sure to have the switch-controller-feature option set to appropriate VLANs:

 

_default <----- default_vlan (vlanid 1).

quarantine <----- quarantine (vlanid 4093).
rspan <----- rspan (vlanid 4092).
voice <----- voice (vlanid 4091).
video <----- video (vlanid 4090).
onboarding <----- nac (vlanid 4089).
nac_segment <----- nac_segment (vlanid 4088).


1.png

 

If all of the above configs are verified and the issue persists, take the backup of FortiManager and contact Fortinet Support TAC.


Related articles:
Displaying the device database.
Technical Tip: The IP Range/Subnet mask of default FortiSwitch VLANs.
Terms & ConditionsAccessibility statement