[pferde]

Ah, ok, I didn't think of systemd version changes. Thanks.

Regarding your rhetorical question about "the same NIC", I think the problem is in determining whether the NIC is the same, and it is not an easy one to solve. I remember that older Suse Linux versions used to pin the interface name to the NIC's MAC address in an udev rule file that got autogenerated when a NIC with a given MAC first appeared on the system, but they stopped doing that.

[tlamponi]

Yeah, the permanent MAC address (i.e., the one the card actually reports to the system not the one dynamic one it can use) would be the safest bet, as that is the most stable thing there is, and more importantly, it is very relevant for switches and firewalls in enterprise settings, so if it changes it's often likely that network access will be broken any way, so one basically can only win with using the MAC as main identifier IMO, at least compared to the current status quo.

[dwattttt]

Sadly a NIC's permanent MAC is known to not always be unique: https://www.howtogeek.com/228286/how-is-the-uniqueness-of-ma...

[tlamponi]

As long as you only got NICs with different permanent MAC addresses installed that does not matter for getting actually long-term stable names.

And for the other case you can still fallback to the other policies, it still will be much more stable by default.

Please note that I don't say that MAC is perfect, but using something that is actually tied to a NIC itself would fare much better by default compared to the NICs position as determined by a bunch of volatile information, and what normally does not matter to me at all, as e.g., I will always use a 100G NIC as ceph private network while the 25G ones as public one, no matter where they are plugged in. That someone configures something by location is the excpection, not the norm.

[dpkirchner]

I don't know if this is still the case but the last time I went without ifnames=0 adding a GPU would cause all the network interfaces to get new names. Junk.