I found a (new) software that finally helps to ban spam that is not blocked by various dns blacklists, greylisting, etc …

Have a look at:
http://tanaya.net/DynaStop/
and the forum:
http://www.exim-users.org/forums/forumdisplay.php?f=36

2007/05/08: Update of my personal DynaStop Whitelist

Here you’ll find a great piece of software, that filters incoming mail on the basis of whether a dynamic IP address is used. This reduces system load and resources in processing unwanted mail because all legitimate mail from mainly all ISPs will be sent from a proper mail exchange server (respectively the dns name). Over 350 million IP addresses were used in testing DynaStop for integrity and stability in identifying dynamic addresses and cross checked false positives.

Although the software is still in beta status, I use it in my company to kick out the rest of unwanted connections that are not recognized by RBLs or those that “survive” greylisting.

Result:

• System load is massive reduced because of less work for spamassassin and antivirus-software
• Connections that come back multiple times and overwit greylisting are banned without scanning the message
• Combined with a daily-report (to control false positives) of blocked networks it’s really a powerful software