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Re: [anti-spam-wg] Domains with MX set to localhost

  • To: der Mouse mouse@localhost
  • From: Markus Stumpf maex-lists-spam-ripe-anti-spam@localhost
  • Date: Thu, 12 Jan 2006 18:25:40 +0100
  • Comment: DomainKeys? See
  • Domainkey-signature: a=rsa-sha1; q=dns; c=nofws; s=testkey;; b=RgfpIY7+uAqA/XH+9q/VkUpYI5+gGDrAUR+pKEtKTZwgaavY4tnp/gV6H3jv7qlZ ;
  • Organization: SpaceNet AG, Muenchen, Germany

On Wed, Jan 11, 2006 at 10:50:38AM -0500, der Mouse wrote:
> How is the second one possible?  An MX record isn't capable of
> containing anything *but* a FQDN.

In theory ;-)

I've seen more than once records like	 IN  MX  10
i.e. an IP address instead of a FQDN in the RHS of the record and mailservers
even connecting to the correct host :)

DJB's dnscache even has the "feature" to map A queries for IP adresses to
IP addresses:
    $ dig
    ;; ANSWER SECTION:               1w14h2m40s IN A
Since we use it on our caching DNS servers for the mailservers (I was
really sick explaining customers 5-10 times a week, why their mails won't
reach the destination, as specified by clueless admins) I don't see
problems with that any longer, but I am sure those kind of records are
still there.


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