On Thu, 21 Oct 2010, Jason W. wrote:
> On Thu, Oct 21, 2010 at 7:26 AM, Jethro R Binks
> <jethro.binks@???> wrote:
>
> > As far as I can see from debugging, the resolver is behaving strangely,
> > but I do not understand why, and I know there are cleverer minds here.
>
> This reverse DNS is badly configured.
Perhaps, but my message focused on a particular point which is quite
specific and I don't understand the way it is reacting, but maybe it is
some sort of catalogue of errors.
> Running dig +tra 5.131.80.194.in-addr.arpa ptr reveals uwrz02 throwing
> the same records over & over again. Here's a snippet.
I've actually thought for a long time there is a more endemic problem
relating to the DNS infrastructure at a higher level, relating to .ac.uk
anyway; I often use squish.net/dnschecker to check domains (including my
own) from a third-party point of view. But if you do, say, an NS search
on strath.ac.uk, there's an awful lot of failure and nested queries higher
up the DNS tree.
(For the .ac.uk people, I tried to engage JANET operations on this, but
they just blamed squish.net, and I haven't found an alternative site that
will do a similar sort of thing to judge against that I can demonstrate to
them, then I got disheartened and did more interesting things with my
life).
J.
> >
> 131.80.194.in-addr.arpa. 85988 IN NS uwrz02.wales.ac.uk.
> 131.80.194.in-addr.arpa. 85988 IN NS uwrz04.wales.ac.uk.
> ;; Received 128 bytes from 194.80.131.2#53(uwrz02.wales.ac.uk) in 111 ms
>
> 131.80.194.in-addr.arpa. 85988 IN NS uwrz04.wales.ac.uk.
> 131.80.194.in-addr.arpa. 85988 IN NS uwrz02.wales.ac.uk.
> ;; Received 128 bytes from 194.80.131.2#53(uwrz02.wales.ac.uk) in 117 ms
>
> 131.80.194.in-addr.arpa. 85987 IN NS uwrz02.wales.ac.uk.
> 131.80.194.in-addr.arpa. 85987 IN NS uwrz04.wales.ac.uk.
> ;; Received 128 bytes from 194.80.131.2#53(uwrz02.wales.ac.uk) in 111 ms
>
> 131.80.194.in-addr.arpa. 85987 IN NS uwrz04.wales.ac.uk.
> 131.80.194.in-addr.arpa. 85987 IN NS uwrz02.wales.ac.uk.
> ;; Received 128 bytes from 194.80.131.2#53(uwrz02.wales.ac.uk) in 123 ms
>
> There is something wrong with uwrz02.wales.ac.uk:
>
> [root@cokecan samba]# dig @uwrz02.wales.ac.uk 131.80.194.in-addr.arpa. ptr
>
> ; <<>> DiG 9.3.4-P1 <<>> @uwrz02.wales.ac.uk 131.80.194.in-addr.arpa. ptr
> ; (1 server found)
> ;; global options: printcmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 27465
> ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
>
> ;; QUESTION SECTION:
> ;131.80.194.in-addr.arpa. IN PTR
>
> ;; Query time: 2315 msec
> ;; SERVER: 194.80.131.2#53(194.80.131.2)
> ;; WHEN: Thu Oct 21 08:02:03 2010
> ;; MSG SIZE rcvd: 41
>
> I can't even reach uwrz04:
>
> [root@cokecan samba]# dig @uwrz04.wales.ac.uk 131.80.194.in-addr.arpa. ptr
>
> ; <<>> DiG 9.3.4-P1 <<>> @uwrz04.wales.ac.uk 131.80.194.in-addr.arpa. ptr
> ; (1 server found)
> ;; global options: printcmd
> ;; connection timed out; no servers could be reached
>
>
> I'm in the southeast USA, so if this is location-specific (e.g.
> anycasting or load-balancing), it may be hard to troubleshoot.
>
> But it doesn't look like it's just you or your exim ;)
>
> --
> HTH, YMMV, HANW :)
>
> Jason
>
> The path to enlightenment is /usr/bin/enlightenment.
>
> --
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>
. . . . . . . . . . . . . . . . . . . . . . . . .
Jethro R Binks, Network Manager,
Information Services Directorate, University Of Strathclyde, Glasgow, UK
The University of Strathclyde is a charitable body, registered in
Scotland, number SC015263.
