Re: [exim] Consider local_domains only if DNS matches

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Author: Peter Thomassen
Date:  
To: exim-users
Subject: Re: [exim] Consider local_domains only if DNS matches
Hi.

Am Montag, 21. Mai 2007 00:11:33 schrieb Phil Pennock:
> Example 1:
> > > > $ host -t mx mail.peter-thomassen.de
> > > > mail.peter-thomassen.de MX      10 mail.a4a.de
> > > > mail.peter-thomassen.de MX      20 rescue.a4a.de
> > > > $ host -t mx mail.glv.at
> > > > mail.glv.at             CNAME   glv.at
> > > > glv.at                  MX      10 mail.a4a.de
> > > > glv.at                  MX      20 rescue.a4a.de
> > > > $

>
> Example 2:
> > $ hostx -t mx sub.glv.at
> > sub.glv.at              CNAME   glv.at
> > glv.at                  MX      20 rescue.a4a.de
> > glv.at                  MX      10 mail.a4a.de
> > $

>
> In example 2, mail for @sub.glv.at should be processed just fine, as
> it's a CNAME pointing to something which resolves.


So, example 2 "valid"?

> In example 1, which is all I'd seen so was what I was commenting upon:
> in the MX RR-set for "mail.peter-thomassen.de" there existed an MX RR
> (priority 10) pointing to "mail.a4a.de"; but "mail.a4a.de" is not a real
> name, it's a pointer to the canonical name (ie: there is a CNAME record)
> of "glv.at".


No, mail.a4a.de resolves directly to 195.225.198.14. The first example
actually is about two requests, one for mail.peter-thomassen.de and one for
mail.glv.at (not for mail.a4a.de!). The difference is that there are MX RR
sets for both peter-thomassen.de and *.peter-thomassen.de, while there is
only one MX RR set for glv.at, mapping subdomains by a wildcard CNAME RR.
This is why I said the example was bad, and suggested to inspect sub.glv.at
(instead of mail.glv.at). -- If I got it right, such policy is allowed.

Bye,
--
      Peter Thomassen • Steigerwaldstr. 4 • 97076 Würzburg • Germany
         http://www.peter-thomassen.de/ • mail@???
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