On 31/01/2020 15:29, Tom Hughes wrote:
> On 31/01/2020 15:23, Steve Dickson wrote:
>
>>> I know there was a change with systemd-networkd in a recent release so
>>> that it now creates a unique but persistent MAC for bridges and maybe
>>> other systems like NetworkManager have done the same?
>> Hmm... this seems odd to me... any idea why this was done?
>
> I believe this is the relevant NEWS entry:
>
>
https://github.com/systemd/systemd/blob/master/NEWS#L926
>
> I think the idea is to ensure that a bridge always has the same
> address, as by default it gets the address of whichever slave
> happens to join first - that's fine in the common case where
> there is one address added at boot and then others come and go
> but may be non-deterministic if multiple addresses are added
> at boot time.
Actually thinking about it the MAC address policy comes from a
link unit so is applied by udev and isn't systemd-networkd specific.
There is an example in that NEWS entry of a link unit to turn
this off and go back to the old behaviour.