[Bug 1821491] Re: DNS lookup fails for local hosts

[Steve Roberts]

Thankyou for all the attention to this and the explanations Dan, but now
I am also confused...

I tend to think that if my desktop is able to successfully lookup the
host on the router (as per
https://bugs.launchpad.net/ubuntu/+source/resolvconf/+bug/1817903) then
I should expect that my laptop on the same lan, should also be able to
do so, hence to me it is still a bug...

So to clarify for me, if nothing else:

If the router dns only has the hostname defined, i.e.
phspi05 192.168.2.35

Lookups by the desktop (no NetworkManager, fixed IP) with resolv.conf containing:
nameserver 192.168.2.1
nameserver 127.0.0.53

dig phspi05 = success
dig phspi05.phs = fail

Lookups by the laptop (with NetworkManager, dhcp assigned IP) with resolv.conf containing:
nameserver 127.0.0.53
search phs

dig phspi05 = fail
dig phspi05.phs = fail

dig phspi05 @192.168.2.1 = success
dig phspi05.phs @192.168.2.1 = fail

If I manually edit resolv.conf on the laptop so that it looks like
nameserver 192.168.2.1
nameserver 127.0.0.53
search phs

dig phspi05 = success

So it seems to me that lookups by systemd-resolved
are failing to lookup the hostname on the local DNS (even if this is by design)

Whatever way I look at it, I have an inconsistency between computers on
the same network.

If the router has the hostname AND domainname defined:
phspi05 192.168.2.35
phspi05.phs 192.168.2.35

then on the desktop
dig phspi05 = success
dig phspi05.phs = success

on laptop
dig phspi05 = fails
dig phspi05.phs = success

I guess I have a workaround to manually edit resolv.conf, and as I don't
reboot that often it is not a big issue, but it doesn't feel right
somehow.

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https://bugs.launchpad.net/bugs/1821491

Title:
  DNS lookup fails for local hosts

Status in systemd package in Ubuntu:
  Invalid

Bug description:
  Mint 19 (Ubuntu Bionic) 
  Laptop so Using NetworkManager, and connecting wirelessly to LAN
  Upgraded from Mint 18.3 so using resolvconf...

  Versions:
  network-manager: 1.10.6-2ubuntu1.1
  resolvconf: 1.79ubuntu10.18.04.3 or 1.79ubuntu10.18.04.2
  systemd: 237-3ubuntu10.15

  dns is specified in NetworkMananager as 192.168.2.1
  the dns is a router, and has static ips assigned to certain hosts on my lan...

  $cat resolv.conf
  nameserver 127.0.0.53
  search phs
  options edns0

  $ nslookup phspi05
  Server:		127.0.0.53
  Address:	127.0.0.53#53

  ** server can't find phspi05: SERVFAIL

  If I explicity specify the dns:

  $ nslookup phspi05 192.168.2.1
  Server:		192.168.2.1
  Address:	192.168.2.1#53

  Non-authoritative answer:
  Name:	phspi05
  Address: 192.168.2.35

  I get the correct ip address...

  Same with dig...

  I would expect that the nameserver set in network-manager would be
  used....

  From tail of $ systemd-resolve --status

  Link 2 (wlp2s0)
        Current Scopes: DNS
         LLMNR setting: yes
  MulticastDNS setting: no
        DNSSEC setting: no
      DNSSEC supported: no
           DNS Servers: 192.168.2.1
            DNS Domain: phs

  So the dns address had been picked up from NetworkManager, but
  apparently is not being used...

  Thought it might be related to this bug:
  https://bugs.launchpad.net/ubuntu/bionic/+source/resolvconf/+bug/1817903

  So installed the proposed fix, but no change. I also tried removing
  package resolvconf, again no change...

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