[Bug 1624320] Re: systemd-resolved appends 127.0.0.53 to resolv.conf alongside existing entries

[henry eko]

Is this behavior related to the bug?
I have running router on 192.168.31.1

Then, I run a test setup of bionic on virtual box as a squid proxy.
Everything fine, almost. 

I found every local network names are failed to be resolved by the new bionic installation, but outside local network names are resolved. 
It is as if the system resolve the domain name to another dns server beyond configuration.

root at rld-proxy:/etc/NetworkManager/dispatcher.d# systemd-resolve --status
Global
          DNSSEC NTA: 10.in-addr.arpa
                      16.172.in-addr.arpa
                      168.192.in-addr.arpa
                      17.172.in-addr.arpa
                      18.172.in-addr.arpa
                      19.172.in-addr.arpa
                      20.172.in-addr.arpa
                      21.172.in-addr.arpa
                      22.172.in-addr.arpa
                      23.172.in-addr.arpa
                      24.172.in-addr.arpa
                      25.172.in-addr.arpa
                      26.172.in-addr.arpa
                      27.172.in-addr.arpa
                      28.172.in-addr.arpa
                      29.172.in-addr.arpa
                      30.172.in-addr.arpa
                      31.172.in-addr.arpa
                      corp
                      d.f.ip6.arpa
                      home
                      internal
                      intranet
                      lan
                      local
                      private
                      test

Link 2 (enp0s3)
      Current Scopes: DNS
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
         DNS Servers: 192.168.31.1

root at rld-proxy:/etc/NetworkManager/dispatcher.d# nslookup dm97-pandorabox
Server:         127.0.0.53
Address:        127.0.0.53#53

** server can't find dm97-pandorabox: SERVFAIL

root at rld-proxy:/etc/NetworkManager/dispatcher.d# nslookup dm97-pandorabox 192.168.31.1
Server:         192.168.31.1
Address:        192.168.31.1#53

Name:   dm97-pandorabox
Address: 192.168.31.1
Name:   dm97-pandorabox
Address: fd76:bf99:23d7::1

Any thoughts?
If any work around produce another bugs, 
I guess it is safe for me to pending upgrade to bionic.

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https://bugs.launchpad.net/bugs/1624320

Title:
  systemd-resolved appends 127.0.0.53 to resolv.conf alongside existing
  entries

Status in systemd package in Ubuntu:
  Confirmed

Bug description:
  systemd-resolved, or more precisely the hook script
  /lib/systemd/system/systemd-resolved.service.d/resolvconf.conf, causes
  resolvconf to add 127.0.0.53 to the set of nameservers in
  /etc/resolv.conf alongside the other nameservers.  That makes no sense
  because systemd-resolved sets up 127.0.0.53 as a proxy for those other
  nameservers.  The effect is similar to bug 1624071 but for
  applications doing their own DNS lookups.  It breaks any DNSSEC
  validation that systemd-resolved tries to do; applications will
  failover to the other nameservers, bypassing validation failures.  And
  it makes failing queries take twice as long.

  /etc/resolv.conf should have only 127.0.0.53 when systemd-resolved is
  active.

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