PPPoE over an unassigned VLAN no longer connects after upgrading to 26.7.3

[downset]

Hello,

after upgrading OPNsense from 26.7.2_2 to 26.7.3, my PPPoE WAN connection stopped working completely. Restoring the Proxmox snapshot containing OPNsense 26.7.2_2 immediately restored the connection without any other configuration or network changes.

Environment

- OPNsense running as a virtual machine on Proxmox
- OPNsense 26.7.2_2: working
- OPNsense 26.7.3 or possibly 26.7.3_1: not working
- The exact hotfix revision is unfortunately unknown
- The WAN connection is passed to the VM through Proxmox bridge `vmbr0`
- The optical termination device is a Luleey 2.5G XPON Stick SFP ONU
- The stick is connected to a UniFi switch

Network topology

The connection is approximately:

Luleey XPON stick → UniFi switch → VLAN 10 → Proxmox vmbr0 → OPNsense VLAN 10 → PPPoE → WAN

VLAN 10 is both:

- the transport VLAN between the UniFi switch and OPNsense, and
- the VLAN required for the provider's PPPoE service.

Inside OPNsense, VLAN 10 is created on the interface connected to `vmbr0`. The PPPoE device uses this VLAN device as its link interface. The VLAN 10 interface itself is not assigned as a separate OPNsense interface; only the resulting PPPoE device is assigned as WAN.

A separate native VLAN is present on the switch port for access to the management interface of the XPON stick. This management VLAN remained unchanged and should not be involved in the PPPoE connection.

Actual behaviour with 26.7.3

After installing the update and rebooting:

- the PPPoE connection remained completely offline;
- no WAN connection was established;
- the VLAN 10 device was still used as an unassigned interface underneath the PPPoE device;
- additional reboots did not restore the connection.

No changes were made to the OPNsense configuration, Proxmox networking, UniFi switch configuration or XPON stick configuration.

Unfortunately, I did not save the PPP logs before restoring the snapshot because I needed to restore Internet access.


Rollback result

I restored the complete Proxmox snapshot containing OPNsense 26.7.2_2. The PPPoE WAN connection came back immediately without changing or rebooting the UniFi switch, XPON stick or any other part of the network.

This makes the issue appear specific to the update from 26.7.2_2 to 26.7.3.

The 26.7.3 changelog includes the interface-related change "resolve VLAN devices indirectly via interfaces_configure()". Could this affect PPPoE devices that use an otherwise unassigned VLAN device as their link interface?

best regards

Downset

[franco]

https://github.com/opnsense/core/issues/10806

[downset]

Thanks for the hint to the git issue.

The patch just released there is fixing the problem.

Thanks for the fast support

best regards

[franco]

Hotfixed in 26.7.3_2.