Re: [exim] Exim server behind NAT router (and HELO)

On Thu, Mar 24, 2005 at 05:37:10PM -0500, Greg A. Woods wrote:
> > It's perfectly acceptable (and indeed very common) for multiple names to map
> > to the same IP address, and for the reverse DNS to have a PTR to only one of
> > those names.
>
> No, it is definitely NOT acceptable (though sadly it is still common for
> such mis-configurations to exist).
>
> The only way the reverse-DNS can be verified is if _ALL_ hostnames have
> valid corresponding PTRs. Period. The logic is inescapable and widely
> accepted and agreed to.

The logic is flawed. If you run a webserver which has 10,000 virtual domains
(a common configuration), you do generally do not put 10,000 PTR records for
that IP address. It would be madness to do so.