DHCPv4 Client PCP not working

[Mika56]

Hi,

I'm trying to set up an OPNsense to replace my ISP provided router combo/box.
My ISP is Orange and I have a FTTH connection, so I followed the following guide: https://docs.opnsense.org/manual/how-tos/orange_fr_fttp.html
However, I'm having trouble marking the DHCP packets with a PCP value of 6, as required.

Here's the value of Options Modifiers on my install:

Code Select Expand

vlan-parent "hn0",vlan-id 832,vlan-pcp 6
(The hn0 interface is connected to my ONT).
When this value is set, I don't see any DHCP Discover packets on the network (for debugging purpose, I've added a switch between the OPNsense server and the ONT, and have a computer running Wireshark. All ports are in trunk mode).

I've made more tests:

• With Options = vlan-parent "hn0", DHCP Discover packets are sent untagged
  
• With Options = vlan-parent "hn0",vlan-id 832, DHCP Discover packets don't seem to be sent
• With Options = (empty)
  
  
  
  • DHCP Discover packets are sent on VLAN 832 but with a PCP value of 0
  • With VLAN's PCP (Interfaces > Other Types > VLAN) set to 6, the DHCP Discover packets are correct (VLAN 832 and PCP value of 6). However, the ISP requires that only the DHCP packets have a priority of 6, not all traffic

These tests make me confident that my setup correctly supports and sets the PCP value. However, it looks like dhclient creates a invalid packet that isn't sent?
Notable information: my OPNsense server is a VM running on Hyper-V.

[Mika56]

Well, I went bare metal to remove the virtualization layer.
The DHCP packets are tagged properly.
I wonder if its a bug in the Hyper-V module or a bug in Hyper-V itself?