Another systemd-resolved problem in 17.04

[Chris Green]

On Thu, Jun 22, 2017 at 10:33:00AM -0400, Robert Heller wrote:
> At Thu, 22 Jun 2017 15:00:46 +0100 "Ubuntu user technical support, not 
> for general discussions" <ubuntu-users at lists.ubuntu.com> wrote: 
> 
> > On Thu, Jun 22, 2017 at 08:40:45AM -0400, Tom H wrote:
> > 
> > ... but why is it switching to a backup DNS server that I haven't specified 
> anywhere? Not to mention why is 
> > is it timing out, 192.168.1.2 is a system on the LAN with nothing else to do except DNS
> 
> Does 192.168.1.2 have a firewall set up?  Is it set up *correctly*?  Eg does 
> it happen to block UDP port 53?

No, it has no firewall and has been working happily providing DNS to
my LAB for a couple of years.  It's not been changed except for
'apt-get' updates for a long time.  It runs Debian.

> 
> What is in the log file for 192.168.1.2?
> 
Loads of DHCP messages and no DNS ones at all.


> The IP6 "backup" DNS might be "hard coded" into the DNS query logic somewhere 
> as a "fall back" (or there might be an obscure conf file with that in it as a 
> [default] "fall back".
> 
My issue *may* be something awry on the LAN that is preventing queries
getting to 192.168.1.2, I'll do some checks to see if I can find
anything.

It would be good to find where the IPV6 fall back comes from though.

-- 
Chris Green