Reverse MX Lookup

[Barry Margolin]

In article <a8ctrc$ce1 at pub3.rc.vix.com>, Erin <erins at hlyw.com> wrote:
>
>Odd problem, we changed our MX record to a different IP address and
>block the old IP address from accepting traffic on port 25. We appear
>to be sending and recieving email without a hitch, but our firewall is
>still blocking attempts on port 25 to the old IP.....
>
>We have searched through our DNS records and have found no legacy MX
>records or even lower cost MX records that would attribute to this.
>
>Anyone know how to lookup all the MX records associated with an IP
>Address?

You can't.  You would have to search the entire DNS hierarchy, which would
be impossible because many sites restrict zone transfers.  And even if it
were possible, it would be impractical due to the size of the DNS
hierarchy.

You could open up the firewall and configure the old server to report the
addresses that are trying to be delivered to it.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Woburn, MA
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