[EXIM] DNS

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Author: Christopher Purnell
Date:  
To: exim-users
Subject: [EXIM] DNS

Exim seems to have a problem with self referring mx records where
there is no corresponding a record. Exim just gets stuck in an
infinite loop doing the same dns lookups and allocating memory as it
goes. Two such bad mx records that I have found are form.com.sg and
intranet.co.uk.

To make it a little clearer what I'm talking about here is the result
of an MX query for form.com.sg.

;; ANSWERS:
form.com.sg.    395291  MX      1 form.com.sg.        ;; THIS LINE
form.com.sg.    395291  MX      0 form-nt.form.com.sg.


;; AUTHORITY RECORDS:
form.com.sg.    81628   NS      secdns.pacific.net.sg.
form.com.sg.    81628   NS      form-nt.form.com.sg.


;; ADDITIONAL RECORDS:
form-nt.form.com.sg.    81628   A       202.42.229.2
secdns.pacific.net.sg.  81628   A       203.120.90.90


And there is no A record for form.com.sg.

The result of this is to bring our mail machines to a halt such that
they need to be rebooted by external means.

--
Christopher John Purnell

--
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