Comment 5 for bug 1907878

I just commended out the line "mystatedir statedir ifindex interface" on both files /etc/network/if-up.d/resolved and /etc/network/if-down.d/resolved

works without issues.

EDIT: ok, I also need to change the return to exit codes...

thomas@ub-tc:~$ sudo systemctl status networking.service
● networking.service - Raise network interfaces
     Loaded: loaded (/lib/systemd/system/networking.service; enabled; vendor preset: enabled)
     Active: failed (Result: exit-code) since Wed 2021-06-09 20:59:35 CEST; 6s ago
       Docs: man:interfaces(5)
    Process: 329244 ExecStart=/sbin/ifup -a --read-environment (code=exited, status=1/FAILURE)
   Main PID: 329244 (code=exited, status=1/FAILURE)

Jun 09 20:59:35 ub-tc systemd[1]: Starting Raise network interfaces...
Jun 09 20:59:35 ub-tc ifup[329283]: /etc/network/if-up.d/resolved: line 20: return: can only `return' from a function or sourced script
Jun 09 20:59:35 ub-tc ifup[329270]: run-parts: /etc/network/if-up.d/resolved exited with return code 2
Jun 09 20:59:35 ub-tc ifup[329244]: ifup: failed to bring up lo
Jun 09 20:59:35 ub-tc systemd[1]: networking.service: Main process exited, code=exited, status=1/FAILURE
Jun 09 20:59:35 ub-tc systemd[1]: networking.service: Failed with result 'exit-code'.
Jun 09 20:59:35 ub-tc systemd[1]: Failed to start Raise network interfaces.