I love the concept, from your post: yeah, I know there are some tiny numbers legit MTA's on those subscriber ip's who just might want to connect to your IMGate, but I reckon 99+% are spammers bypassing thier access providers SMTP gateway and sending from home directly to MX's, ie, what mail-abuse.org calls DUL, dial-up-lines.
Yeah and since I'm a non profit I deal with these weenies and STILL say most DHCP MTAs are spam, I'll run the check but I need a whitelist way around it somehow. Cant circumvent/whitelist a header check, no? But I'd love to implement anything you write and dump my logs in my ftp dir so you can cron-snatch them and review the fruits of your labors and see it's efficacy. Am down to about 20-30 rejected mails a day since I run over 75-100 IPTables rules as to what as*holes can talk to my mail server. The Far East pretty much cant talk to it period. But I would implement and help debug(respectfully) wherever I can Excellent idea -A
