Yes, that's precisely what I mean. Yes, of course almost home email has originated from a home/dynamic IP, but I do want the last-hop before my mail server to look like a real mail server.
There are blacklist providers who keep specific lists of home or dynamically-allocated IP networks that the big ISPs use which you can subscribe to, but I simply block everything with a certain kind of name from Comcast.com, RR.com and with something that looks like an IP address in the name (such as 123-456-789.crappy.isp.com). Some antispam engines allow you to block anything that's ever traversed a known-spamming network, but I'm not quite that stringent.
If places like Comcast in the US forced people to logon to their mail servers every time they sent a message (obviously you can set up the mail client to logon for you), the amount of spam that tries to come into my organisation (in Australia) would instantly drop by about 15%
My check is pretty crude - it's not the kind of thing I'd do if I were an actual email service provider - but I get rid of 70% of inbound message traffic just from that check, and have a list of less than a dozen "false positives" over the last 5 years. When you're talking getting rid of several thousand messages a day, and only having 10 or so false-positives out of literally millions of connections, I think the blunt tool can be pretty useful (if it's well-maintained).
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There are blacklist providers who keep specific lists of home or dynamically-allocated IP networks that the big ISPs use which you can subscribe to, but I simply block everything with a certain kind of name from Comcast.com, RR.com and with something that looks like an IP address in the name (such as 123-456-789.crappy.isp.com). Some antispam engines allow you to block anything that's ever traversed a known-spamming network, but I'm not quite that stringent.
If places like Comcast in the US forced people to logon to their mail servers every time they sent a message (obviously you can set up the mail client to logon for you), the amount of spam that tries to come into my organisation (in Australia) would instantly drop by about 15%
My check is pretty crude - it's not the kind of thing I'd do if I were an actual email service provider - but I get rid of 70% of inbound message traffic just from that check, and have a list of less than a dozen "false positives" over the last 5 years. When you're talking getting rid of several thousand messages a day, and only having 10 or so false-positives out of literally millions of connections, I think the blunt tool can be pretty useful (if it's well-maintained).