Problem with update 6.3-2

[proxuser2]

Newest kernel breaks somehow my networking. I managed to get it working by changing kernel at boot.

Working fine:

Linux proxmox 5.4.65-1-pve #1 SMP PVE 5.4.65-1 (Mon, 21 Sep 2020 15:40:22 +0200) x86_64

root@proxmox:~# systemctl status networking
● networking.service - Network initialization
   Loaded: loaded (/lib/systemd/system/networking.service; enabled; vendor preset: enabled)
   Active: active (exited) since Thu 2020-11-26 22:35:00 EET; 10min ago
     Docs: man:interfaces(5)
           man:ifup(8)
           man:ifdown(8)
  Process: 644 ExecStart=/usr/share/ifupdown2/sbin/start-networking start (code=exited, status=0/SUCCESS)
Main PID: 644 (code=exited, status=0/SUCCESS)

Nov 26 22:35:00 proxmox systemd[1]: Starting Network initialization...
Nov 26 22:35:00 proxmox networking[644]: networking: Configuring network interfaces
Nov 26 22:35:00 proxmox systemd[1]: Started Network initialization.

Not working:

 

[H4R0]

Reboot with the new kernel, check output of "ip a" for new device name and update /etc/network/interfaces accordingly.

If "ip a" doesnt output a device name like "enoX", "ethX" etc. then the nic driver is missing in the new kernel.

 

[Stoiko Ivanov]

In addition to what @H4R0 said - ever since predictable network names https://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/ were introduced it can happen that an interface name changes unexpectedly between kernel versions
check the output of ip a or ip link - and change the bridge-ports in /etc/network/interfaces accordingly