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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http://www.exim.org/ ***