One more note of clarification:
[ On Tuesday, April 2, 2002 at 13:55:54 (+0100), John Horne wrote: ]
> Subject: [Exim] Exim4: helo_verify/host_lookup reverse lookups
>
> the DNS will return the PTR records in a random order.
Nope -- PTR records are supposed to always be returned in the same order
they're listed in the zone file, and in most DNS resolver APIs the first
one is known as the "official" hostname. Ideally that'll be the name
the host knows of itself as (i.e. w.r.t. SMTP the one it puts in the 220
banner it gives to connecting SMTP clients and the one it uses as the
HELO/EHLO parameter when it connects to SMTP servers).
In your example that's exactly what happens, so all should be fine:
$ telnet 141.163.66.134 25
Trying 141.163.66.134...
Connected to mary.csd.plymouth.ac.uk.
Escape character is '^]'.
220 mary.csd.plymouth.ac.uk ESMTP Exim 3.35 #1 Wed, 03 Apr 2002 03:32:34 +0100
quit
221 mary.csd.plymouth.ac.uk closing connection
Connection closed by foreign host.
--
Greg A. Woods
+1 416 218-0098; <gwoods@???>; <g.a.woods@???>; <woods@???>
Planix, Inc. <woods@???>; VE3TCP; Secrets of the Weird <woods@???>
