[Bug 1823503] Re: systemd-resolved ignores /etc/network/interfaces on Ubuntu 18.04

[Dan Streetman]

For new installations, the /etc/network/interfaces file does have text
explaining that ifupdown is no longer used and network config is now
done via netplan.

For upgrades of systems using ifupdown, it is not removed, and should
still manage the networking, and changes to /e/n/i should still work.

To address your bug that systemd-resolved ignores any settings in e/n/i,
that's correct that systemd-resolved will not *directly* look at the
e/n/i config to find nameserver configuration.  However, if ifupdown is
managing your system networking, then it will provide nameserver details
to systemd-resolved.  The specific mechanism depends on your specific
network configuration (e.g. static vs dhcp) and if you have resolvconf
installed or not.

If you are having a specific problem with your system networking, please
feel free to add details about what is wrong.

** Changed in: systemd (Ubuntu)
       Status: New => Incomplete

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to systemd in Ubuntu.
https://bugs.launchpad.net/bugs/1823503

Title:
  systemd-resolved ignores /etc/network/interfaces on Ubuntu 18.04

Status in systemd package in Ubuntu:
  Incomplete

Bug description:
  dns-nameservers entry in /etc/network/interfaces is ignored by
  systemd-resolved-- all of the other settings work, which adds quite a
  bit of confusion and frustration since Ubuntu recently switched to
  using netplan.

  
  It would be a **VERY** good idea to add a comment at the top of /etc/network/interfaces that this file is now deprecated, and provide information about the new netplan utility. Something similar was done to /etc/resolv.conf years back.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1823503/+subscriptions