Re: [exim] Odd resolver issue, I think

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Author: Jethro R Binks
Date:  
To: exim-users
Subject: Re: [exim] Odd resolver issue, I think
On Thu, 21 Oct 2010, Ted Cooper wrote:

> Is this even valid??


Yeah it's a funny one. I actually spoke to them about in February this
year too, but I didn't hear much back and either it went away, or it's
been lingering since then.

> Multiple records are ok, but the * contain records? That really doesn't
> seem right. Almost like someone forgot to take into account those kind
> of records in the forward lookup zone when writing a script to
> automatically create the reverse zone.
>
> All the DNS tools are perfectly fine resolving it but it still seems
> bonkers. Ah, but Exim can't .. at least in any test I can throw at it in
> a couple of minutes.


I don't get why the debugging of the query response says:

;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 53692
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2
;;      *.test.wales.ac.uk, type = A, class = IN
*.test.wales.ac.uk.     41m45s IN A     194.80.131.5
...


but then you get:

10:39:58 23259 gethostbyname2(af=inet) returned 3 (NO_RECOVERY)

gethostbyname2 appears to be deciding that NO_RECOVERY is appropriate,
even though an answer to "*.test.wales.ac.uk." was received and DNS
appears happy.

> Exim shouldn't bug out or error on this - perhaps it should be ignoring
> garbage results and just be happy the rest being ok .. except apparently
> these aren't garbage results. :/ I can't for the life of me find an RFC
> past 1035 (wasn't it deprecated? Or was that the email one) that allows
> a * to be part of a valid hostname and hence listed as PTR data.


We need Tony, sage of DNS to clear the mist :).

> I'd shoot the person who put all that cruft in the in-addr.arpa zone
> file ;) Remove it and Exim should be happy again. I really don't know if
> we should consider it a bug in Exim though.


It doesn't appear to be Exim so far as I can see, but the resolver
library. Whether it is correct to grumble or not is what I'm really after
finding out.

Jethro.

. . . . . . . . . . . . . . . . . . . . . . . . .
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.