Problem with multi-wan PPPoE interfaces since 24.7.11

[andrewhotlab]

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Describe the bug

We have two WAN interfaces, both configured as PPPoE clients. Both providers assign the same IPv4 address as default gateway. Since we upgraded to OPNsense 24.7.11, only one link can be used at the same time. We downgraded to 24.7.10 and the problem disappeared.
No problem in another setup, were both PPPoE interfaces receive different gateway IP addresses.

We guess that the cause is in one of these changes, but we have no clue about what of them.

To Reproduce

Upgrade OPNsense from 24.7.10 to 24.7.11

Expected behavior

Traffic flow on both WAN interfaces.

Screenshots

[AdSchellevis]

We have two WAN interfaces, both configured as PPPoE clients. Both providers assign the same IPv4 address as default gateway. Since we upgraded to OPNsense 24.7.11, only one link can be used at the same time.

This isn't new, you just can't have two identical upstream gateways.

[andrewhotlab]

It absolutely makes sense, but that setup has been working fine until version 24.7.11… what might be the commit which changed this behavior?

[Monviech]

#5238

[andrewhotlab]

Thank you very much @Monviech, but it does not help me understand why that setup has been working until the latest update.
In the mean time, I found that the "disruptive" change is not inside the opnsense-24.7.11 package, but in kernel-24.7.10-amd64.pkg. If I remember correctly, it has been a problematic version, fixed on 4th December 2024: https://forum.opnsense.org/index.php?topic=44413.msg221775#msg221775

Sorry for my ignorance: where are sources which the kernel package is built from?

[AdSchellevis]

https://github.com/opnsense/src