> > However, the ISP dynamic address tests *do* belong in the MTA RBL > checks. The fraction of legitimate emails received from dynamic-IP > hosts is vanishingly small compared to the tens or hundreds of > thousands of compromised Windows boxen spewing spam and viruses... >
Sorry to poke in on the thread, but I disagree. Most small start-up businesses buy business class DSL these days with 1-5 fixed IP addresses. They often have small firewalls, anti-virus, most everything they should have. They probably don't have a full time IT staff. There are a lot of small businesses on these legitimate business class DSL lines with fixed IP addresses (which they pay extra for) who are very frequently incorrectly listed as "dynamic" IP addresses. The vast majority of these small companies are NOT spammers. To expect every small start-up to be on a major Internet carrier with a T1 is simply not reality these days. To block on dynamic is asking for a lot of trouble. It also is a pay-to-play mentality. If a start-up business can't afford a T1 then they can't send email? If you are a system admin and you flat-out reject email that shows on various error ridden "dial-up" lists as "dynamic" IP address for a company, other than your own, you should be fired IMO.
