Re: [Exim] Exim4: helo_verify/host_lookup reverse lookups

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Author: John Horne
Date:  
To: Exim Users Mailing List
Subject: Re: [Exim] Exim4: helo_verify/host_lookup reverse lookups
On 03-Apr-2002 at 02:33:32 Greg A. Woods wrote:
> 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).
>

I don't think so:

{john}1: dig -x 141.163.66.134

; <<>> DiG 9.2.1rc1 <<>> -x 141.163.66.134
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 35687
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 4, ADDITIONAL: 4

;; QUESTION SECTION:
;134.66.163.141.in-addr.arpa.   IN      PTR


;; ANSWER SECTION:
134.66.163.141.in-addr.arpa. 21250 IN   PTR     mary.csd.plymouth.ac.uk.
134.66.163.141.in-addr.arpa. 21250 IN   PTR     mail.plymouth.ac.uk.


;; AUTHORITY SECTION:
163.141.in-addr.arpa.   45593   IN      NS      dns1.plymouth.ac.uk.
163.141.in-addr.arpa.   45593   IN      NS      dns2.cs.strath.ac.uk.
163.141.in-addr.arpa.   45593   IN      NS      dns0.plymouth.ac.uk.
163.141.in-addr.arpa.   45593   IN      NS      dns1.cs.strath.ac.uk.


;; ADDITIONAL SECTION:
dns0.plymouth.ac.uk.    85894   IN      A       141.163.1.250
dns1.cs.strath.ac.uk.   8148    IN      A       130.159.196.126
dns1.plymouth.ac.uk.    85894   IN      A       141.163.165.131
dns2.cs.strath.ac.uk.   8146    IN      A       130.159.196.125


;; Query time: 98 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Wed Apr 3 09:05:36 2002
;; MSG SIZE rcvd: 251

{john}2: dig -x 141.163.66.134

; <<>> DiG 9.2.1rc1 <<>> -x 141.163.66.134
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 44348
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 4, ADDITIONAL: 4

;; QUESTION SECTION:
;134.66.163.141.in-addr.arpa.   IN      PTR


;; ANSWER SECTION:
134.66.163.141.in-addr.arpa. 21249 IN   PTR     mail.plymouth.ac.uk.
134.66.163.141.in-addr.arpa. 21249 IN   PTR     mary.csd.plymouth.ac.uk.


;; AUTHORITY SECTION:
163.141.in-addr.arpa.   45592   IN      NS      dns2.cs.strath.ac.uk.
163.141.in-addr.arpa.   45592   IN      NS      dns0.plymouth.ac.uk.
163.141.in-addr.arpa.   45592   IN      NS      dns1.cs.strath.ac.uk.
163.141.in-addr.arpa.   45592   IN      NS      dns1.plymouth.ac.uk.


;; ADDITIONAL SECTION:
dns0.plymouth.ac.uk.    85893   IN      A       141.163.1.250
dns1.cs.strath.ac.uk.   8147    IN      A       130.159.196.126
dns1.plymouth.ac.uk.    85893   IN      A       141.163.165.131
dns2.cs.strath.ac.uk.   8145    IN      A       130.159.196.125


;; Query time: 70 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Wed Apr 3 09:05:38 2002
;; MSG SIZE rcvd: 251


The first gives 'mary', the second 'mail'.


Regards,

John.

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John Horne, University of Plymouth, UK           Tel: +44 (0)1752 233914
E-mail: jhorne@???
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