Re: [exim] Odd resolver issue, I think

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Author: Jason W.
Date:  
To: exim-users
Subject: Re: [exim] Odd resolver issue, I think
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.

Running dig +tra 5.131.80.194.in-addr.arpa ptr reveals uwrz02 throwing
the same records over & over again. Here's a snippet.

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.