Hyper-V not forwarding VLan tags to virtual machine

Question

Hyper-V not forwarding VLan tags to virtual machine

Jason Doleshall 0

I am attempting to setup a virtual firewall on the Hyper-V guest. The guest is connected to 1 virtual Nic but the vm has multiple vlans attached to that interface. The host seems to be removing the tag from the traffic either as it leaves the vm or as it returns. I have other guest that use the same trunk from the physical switch utilizing the vlan IT in the hyper-v settings and they work fine it just seems to be when passing the tagged traffic to and/or from the vm. I have set the virtual adapters as trunk but the traffic still doesn't seem to make it there does anyone have any insight?

Paul Lovelace 0 Reputation points

2024-05-29T14:45:31.5+00:00

I'm having a similar issue. I've used Set-VMNetworkAdapterVlan -Trunk -NativeVlanId 1 -AllowedVlanIdList 1-100 -VMName "Test-vm" and I can use Wireshark to verify that my Windows 2022 guest is getting all the traffic, but there are no tags on the non-native VLANs.

If I install a Linux server with the same settings it IS getting tagged traffic.

How do I get the Windows Guest's network driver to stop stripping the VLAN headers?
Jason Doleshall 0 Reputation points

2024-05-29T14:53:37.7366667+00:00

The issue I had I'm resolving by switching from the sonicwall appliance to fortigate.

Paul you may try to remove vlan 1 from the allow list as far as I know you can't put the native in the allowlist.
Paul Lovelace 0 Reputation points

2024-05-29T15:32:09.88+00:00

I tried it with Native set to 0 and then defined the VlanID in Windows and the VLAN is still being stripped. For the time being I'm just using Linux to capture the traffic I need, but Windows is super annoying because every driver has a different way to suppress stripping the VLAN and the Hyper-V adapter simply doesn't seem to have a way to suppress it.

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Paul Lovelace 0 Reputation points

2024-05-29T14:45:31.5+00:00

I'm having a similar issue. I've used Set-VMNetworkAdapterVlan -Trunk -NativeVlanId 1 -AllowedVlanIdList 1-100 -VMName "Test-vm" and I can use Wireshark to verify that my Windows 2022 guest is getting all the traffic, but there are no tags on the non-native VLANs.

If I install a Linux server with the same settings it IS getting tagged traffic.

How do I get the Windows Guest's network driver to stop stripping the VLAN headers?
Jason Doleshall 0 Reputation points

2024-05-29T14:53:37.7366667+00:00

The issue I had I'm resolving by switching from the sonicwall appliance to fortigate.

Paul you may try to remove vlan 1 from the allow list as far as I know you can't put the native in the allowlist.
Paul Lovelace 0 Reputation points

2024-05-29T15:32:09.88+00:00

I tried it with Native set to 0 and then defined the VlanID in Windows and the VLAN is still being stripped. For the time being I'm just using Linux to capture the traffic I need, but Windows is super annoying because every driver has a different way to suppress stripping the VLAN and the Hyper-V adapter simply doesn't seem to have a way to suppress it.

Answer 1

Hi Jason, Thanks for your post. Generally speaking, starting in Windows 11, version 22H2, Hyper-V firewall is a network firewall solution that enables filtering of inbound and outbound traffic to/from containers hosted by Windows, including the Windows Subsystem for Linux (WSL). Please refer the following article to see how to configure Hyper-V firewall rules and settings using PowerShell or configuration service provider (CSP). Create and configure a virtual switch with Hyper-V | Microsoft Learn Best Regards, Ian Xue

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Answer 2

Mike Russo 16

Set-VMNetworkAdapterVlan -Trunk -NativeVlanId 0 -AllowedVlanIdList 1-100 -VMName "Test-vm"

I had to set the native VLAN to 0 before untagged traffic was allowed to get into my guest, along with tagged traffic that I handle on the guest. (my guest is Linux though)

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Hyper-V not forwarding VLan tags to virtual machine

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