This does the same thing as greylisting except it is far faster and
takes no software to make it work. It's so simple that you have to see
it to believe it. It's just a change in MX records. The idea to to add
dummy MX records that point to IP addresses with port 25 closed.
The lowest one always fails. Within seconds you try the second one and
it works. The high ones are also dead but a lot of spammers try the
highest MX first because it might have less spam filtering. The extra
ones is for random MX access.
Takes a few minutes to set and the spam goes away and without the delays
and complexity of greylisting.
