Spamhaus is in da house.

About a week ago I turned on a feature of my mail server that checks the source of incoming email against a realtime blackhole list, specifically that provided by Spamhaus. So far its been a great success and I'm now catching 50 to 100 bogus spam emails per day.

In case you don't know a realtime blackhole list contains a big list of all known sources of spam and can be queried by IP address via a DNS lookup. SpamHaus offers this service free to low volume users (even commercial ones) and suppliments it with an exploits block list. This list contains IP addresses that are know to have been taken over by viruses, trojans, worms and other exploits that send out spam.

The only problem I've had so far is that Ziff Davis is sending out their ExtremeTech and eWeek publications from an IP address listed in the SpamHaus RBL. Fortunately I've configured my mail server to send me a copy of all emails that are rejected while the sender gets the usual SMTP error. So it looks to the sender as if the email was never delivered - hopefully discouraging further spam and moving my email addresses of spammers lists (fingers crossed). But getting a copy of the email rejected does allow me to check for problems like the Ziff Davis situation. I've alerted ZD to the problem, or rather attempted to since the do not list any technical contacts on their web sites, just marketing and sales people.