[Exim] Kool Spam Catching Trick

I had a brilliant idea to catch a lot of spam and it seems to work.

What I did was set a secondary MX record to be another IP on the same
computer as my primary email server. I had noticed that some spammers
often will email the secondary rather than the primary MX believing that
the secondary has less filtering. In my case there never is a time when
the secondary is up and the primary is down. So - anything coming into
the secondary is spam.

I did a test and it seems to work. I searched my spam pile and had 8907
matches on the secondary. But searching the ham pile I got 0 matches.

The only issue is if I were really down for some time I might want to
disable this trick for a few hours after coming back up.