hippy wrote: ↑Tue Aug 22, 2017 8:40 am
If they had provided well defined names alongside the traditional names there would have been no issue.
Except for every existing program that deals with network interfaces, which would suddenly see twice as many and have no reason to suspect that half of them are duplicates. Your proposal requires changing the kernel interface, and everything that uses it.
(Link allows you to rename an interface, or create side interfaces such as vlans and bridges. It does not give an interface two names.)
epoch1970 wrote: ↑Tue Aug 22, 2017 10:43 am
There was no "risk" using multiple interfaces because the way to set distinguishable names was to add udev rules to name your interfaces according to MAC address. Udev did that automatically for the first interfaces, in 70-persistent-net-rules.
Anything that requires manual udev rules is unusably broken. The auto-generated rules were okay, but there was no guarantee they would be the same across multiple installs. (If you had upgraded to stretch instead of reinstalling, you would still have your persistent eth0 rule from jessie.)
I was going to agree with everyone that it is crazy for Debian to add NamePolicy=mac, when the default in upstream systemd and other distros is never to use mac. However, it turns out that Debian have not added mac to NamePolicy. Instead they have a custom udev rule that applies only to USB NICs.
For all non-Pi platforms, this is actually quite a good default. If you have a USB NIC, you are probably using it intermittently, and you would not expect it to be firewalled differently, say, depending on which port you plug it in.