Another systemd-resolved problem in 17.04

[Chris Green]

On Thu, Jun 22, 2017 at 11:13:47PM +1000, Karl Auer wrote:
> On Thu, 2017-06-22 at 12:11 +0100, Chris Green wrote:
> > On Thu, Jun 22, 2017 at 07:02:39PM +1000, Karl Auer wrote:
> > > It is barely possible that the nameserver is refusing to answer
> > > queries that arrive over IPv6 transport. If you control that
> > > nameserver you should certainly check its configuration. You could
> > > also see what happens when you query the same nameserver on its
> > > IPv4 address or (if it has one) its non-link-local address.
> > > 
> > So are you saying that the nameserver that's responding with REFUSE
> > is 'out there' on the internet somewhere?  If so I'm surprised as I
> > have IPV6 support turned off in my router so I don't understand how
> > IPV6 packets can be sent and received at all.
> 
> I'm saying that you clearly ARE communicating over IPv6 in spite of
> your best efforts. And the nameserver you are communicating with has
> the link-local address you mentioned. And it is possible, though
> unlikely, that the nameserver is refusing service based on the query
> transport - IPv6. It is more likely that it is configured to provide
> service only to a restricted set up IP addresses, and the IPv6 address
> isn't in that set.
> 
> But to be honest it's all a bit mysterious :-)
> 
Quite, it's only started happening recently and is very intermittent,
most of the time everything works just fine.  I see the odd result of
a DNS failure in leafnode when it fetches news and in a script I have
that scans my catchall mailbox.  Since these get run by cron at
intervals anyway no harm results.

However, yesterday, I had a session on my laptop where something like
half my DNS lookups were failing.

I think my *basic* issue is the DNS at 192.168.1.2 not responding
quickly enough for whatever reason.  I'll try and run some tests to
see if something is awry on the LAN.

-- 
Chris Green