Firewall VM with network bridge with multiple different VLA configs

Jun 4, 2026
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Hi all,

I need to migrate a virtual Firewall to PROXMOX from Hyper-V.
My proxmox server has 3 NICs physical NICs (LAN1, DMZ, Internet).
The Firewall VM has
- one NIC to Internet
- one to DMZ and
- 7 NICs connected to LAN1:
3 NICs are without VLAN config
3 NICs are with VLAN Access config
1 NIC has Trunk config with about 10 tagged VLANs.
How do I do that with Proxmox PVE?

I have lots of configs with VLAN access configs which is easy: Set VLAN on VMs NIC and fine.
But how do I config a Trunk config?
This must be done for only one VM NIC....

I found that:
Editing /etc/pve/qemu-server/vm-id.conf

net3: virtio=00:00:00:00:00:00,bridge=vmbr0,trunks=10;20;30;100
net4: virtio=00:00:00:00:00:00,bridge=vmbr0,tag=45
net5: virtio=00:00:00:00:00:00,bridge=vmbr0,tag=46

So easy?!

Thanks for hints
Gernot
 
Last edited:
Hi @gernotmeyer67

thanks for posting in the forum!

So easy?!
it's even easier ;)
Just don't add any VLAN tag and put the virtual NIC of the VM on the appropriate vmbr interface.
The VM can then send out Ethernet frames with any VLAN tag.
Disclaimer: Of course the VM then has to add its VLAN tags itself, it is not handled by the host.

Yours sincerely
Jonas