[Mimedefang] Only MX record is fake

[Ben Kamen]

On 2011-11-17 3:05 PM, dfs at roaringpenguin.com wrote:
>> Those people checking for valid MX records for a sender's domain from
>> within MIMEdefang ... is anybody checking if a sender's one and only MX
>> record is a fake MX tempfailing service? Has anyone ever seen this type
>> of setup for legitimate e-mail?
>
> Our commercial product has a setting to reject mail from any domain
> that has an MX record that resolves back to 127.0.0.0/8 or ::1.  We've
> had no false-positives reported.
>

A long time ago, I remember reading that having a backup MX to localhost was to send spammers spinning to themselves eventually if your server rejected them.

it was a funny read -- but not sure how usable now..

This thread reminded me of that and why someone my  have 127.0.0.1 as a lower priority MX.

  -Ben