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[_] DNS resolving oddity

Amias Channer me at amias.net
Mon Nov 6 10:28:15 GMT 2017

Hello _,

Maybe their previous DNS admin left in a hurry.

Cheers
Amias

On 6 Nov 2017 09:45, "Craig Francis" <craig at craigfrancis.co.uk> wrote:

> True, but it’s been like this for over a week (took them a week to say
> everything is fine)... so I doubt they are making changes :-)
>
>
>
> > On 6 Nov 2017, at 9:35 am, Amias Channer <me at amias.net> wrote:
> >
> > Hello _,
> >
> >
> > Low TTL is usually set when expecting to make a lot of changes, then you
> > crank it back up again when settled
> >
> > Cheers
> > Amias
> >
> >> On 6 Nov 2017 09:12, "Craig Francis" <craig at craigfrancis.co.uk> wrote:
> >>
> >> Thanks for confirming Oliver,
> >>
> >> I’m trying to help the company who (not surprisingly) had DNS issues
> last
> >> week, and the setup seems odd (the 20s TTL seems wrong to me as well).
> >>
> >> This was just the first time I’ve seen a setup where you could get
> another
> >> Authority response when asking for an A record (i.e. after doing the NS
> >> lookups, and being told who should be the authority for that domain).
> >>
> >> And I’m running OSX as well, so not sure why I was needing the +noedns
> >> flag.
> >>
> >> Craig
> >>
> >>
> >>
> >>> On 5 Nov 2017, at 10:59 pm, Oliver Humpage <oliver at watershed.co.uk>
> >> wrote:
> >>>
> >>>
> >>>> On 5 Nov 2017, at 17:45, Craig Francis <craig at craigfrancis.co.uk>
> >> wrote:
> >>>>
> >>>> We finally get the answer, but this seems a bit weird/broken to me...
> >> yet somehow it works (for all?).
> >>>
> >>> I guess your concern is that a DNS server that should be authoritative
> >> for the domain isn’t returning an answer.
> >>>
> >>> However, what it is returning (an Authority section) is exactly what
> >> both the root and .com DNS servers returned. Therefore the client will
> >> simply carry on following the chain and ask one of the servers in the
> >> authority section, which as you noted works fine (on OS X I didn’t need
> the
> >> +noedns flag).
> >>>
> >>> So it’s slightly odd, but it’s all within spec. Of more concern is the
> >> 20s TTL, which is insanely low. Whatever you’re doing that requires that
> >> low a TTL, do it another way, cos that’s not really how DNS is meant to
> >> work :)
> >>>
> >>> Oliver.
> >>>
> >>> --
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