Its called "NOLISTING" - but does it work?
An experiment was carried out on a small throughput server. Here is the
conclusion: https://www.hmailserver.com/forum/viewtopic.php?p=185262#p185262
(You'll be surprised).
On 05/03/2017 06:32, Rob Gunther wrote:
We have run our servers with a decoy, our MX records have been like
this for 10+ years:
mx0.example.com <http://mx0.example.com>
mx1.example.com <http://mx1.example.com>
mx2.example.com <http://mx2.example.com>
mx1 & mx2 are real servers. mx0 is nothing, it points to an IP
address that is controlled by us but there is no server.
The concept being that some spammers attempt that server, get nothing
and don't bother trying any other server.
This has been fine for a decade.
