Re: [qmailtoaster] Best way to deny residential smtp servers

[Jake Vickers]

Isreal Varela wrote: Hi all,   Could someone give me a hint as to the best way to deny mail from SMTP Servers unning from residential IP’s.   I get a ton of mail from res.rr.com. I tried to put it in the badmailfrom but the e-mail sender address changes so much it is not possible to keep up.   I would suggest adding a rule for open relays, and maybe a couple other DNS-BL's. Check out my page (old now) at v2gnu.com/qmail You can also get the IP address of one of the spammers, and go to dnsstuff.com and do a whois lookup on them. It will tell you that (for example) the IP address 24.66.127.3 belongs to Shaw cable, and that they own the 24.64.0.0/13 range. You could write an iptables rule to block the whole subnet that way. That will stop anyone from their IP addresses from connecting to your machine at all. Not the "correct" way to do things, but widely used. The proper thing to do is contact the admin at Roadrunner and report the spammer. They do take action; my neighbor got a phone call to fix the problem with his computer (he was sending out spam messages due to a virus), or they were going to disconnect his service in 24 hours.