FortiGate: VLAN Tagged on LAG, Untagged on Switch Port

Forum|Forum|11 months ago
September 11, 2025
3 replies
465 views

I have a TRUNK-LAG configured for Aggregate mode. This interface contains VLANs 40–48. I want to add VLAN 49 as tagged on the TRUNK-LAG and untagged on SWVL-49. How can I do this?

Screenshot 2025-09-11 144206.png

Screenshot 2025-09-11 144048.png

FortiGate

Best answer by AEK

As I said above, if you want it untagged you need to set the IP address 172.18.88.254 directly on the SWVL-49 interface, not on the VL-49 VLAN interface.

AEK

SuperUser

To add tagged VLAN 49, click Create New > Interface, then:

Type: VLAN
VLAN ID: 49
Interface: Trunk-LAG
IP/Mask: x.x.x.x/x

For the untagged one, just set the IP address of the Trunk-LAG interface with the related IP address (instead of 0.0.0.0/0) and you are done.

AEK

officeitAuthor

Explorer

Screenshot 2025-09-11 144206.png
For this time i try to plug in on port5 i cannot get ip. Do you want to get more some detail ?

AEKAnswer

SuperUser

As I said above, if you want it untagged you need to set the IP address 172.18.88.254 directly on the SWVL-49 interface, not on the VL-49 VLAN interface.

AEK

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