Jayson Smith writes: > Comcast/Charter (found out about that one Saturday night when > trying to reply to a legit individual message) both reject the > message as soon as a blocked server connects,
Comcast is really bad for any number of reasons. Unfortunately, if I remember correctly they're effectively a monopoly ISP for broadband in parts of the country. Never heard of Charter. > Microsoft, when they decide you're evil and put you on their > internal blacklist, reject after Mail from:. That's bizarre. Even though I have no respect for the morals or technology of Microsoft "security" in the broadest sense, the only sensible reason for blocking at that point (rather than connect or HELO) I can think of is that they do a lookup on the SPF record for the domain in MAIL FROM and block based on "From alignment". I assume you've checked and rechecked that, but if not, check your SPF record. > I find these rejections quite annoying, because clearly this means > their spam analytics software is missing out on a lot of details > that could help them make a more informed decision about whether to > accept the message. The quantity of spam that they're handling is mind-boggling. In 2014, the head of email security at Yahoo (who is very good; disclaimer, she gave me a kitten many decades ago :-) reported to the DMARC working group at IETF that after a different department leaked half a billion contact lists to spammers (who used them for "recommended by a friend" spam), they were facing sustained campaigns of more than 1 million spams per minute. In that context, finding ways to block on connect makes sense. What I don't understand is why they don't use rate-limiting techniques where possible (ie, if they're not being DOS'ed). For example, at first contact, temporary failure for 15 minutes. Upon retry (which typically will take 4 hours in most MTAs' default configuration), it's accepted and if not spam, it's delivered to the recipient(s) and the source whitelisted. If it *is* spam, you go back on the greylist with longer and longer delays as a higher proportion of spam is detected. If no legit mail is found, eventually you go on the blacklist. > But oh no, if your IP is on one of the blacklists we check, I doubt the folks who provide email as an opt-in service (Gmail, Microsoft) take RBLs very seriously. They're in the business of profiling traffic, and it makes sense and dollars to profile everybody, customers and non-customers. That's the only way I can make sense of the way sometimes Microsoft will magically unblock you after stonewalling for days or weeks. The ISPs who provide email because that's what ISPs do aka Comcast I wouldn't be surprised, though. > Go away and don't come back until you've solved your spam problem > that probably isn't even your problem. Goodbye! Unfortunately email addresses aren't portable, although it wouldn't be hard to make them so. Sure, many customers would stick with their ISP mailboxes despite losing mail, but for people willing to invest in better service the big cost to switching email providers is getting their correspondents to update contact lists. Steve ------------------------------------------------------ Mailman-Users mailing list -- mailman-users@python.org To unsubscribe send an email to mailman-users-le...@python.org https://mail.python.org/mailman3/lists/mailman-users.python.org/ Mailman FAQ: http://wiki.list.org/x/AgA3 Security Policy: http://wiki.list.org/x/QIA9 Searchable Archives: https://www.mail-archive.com/mailman-users@python.org/ https://mail.python.org/archives/list/mailman-users@python.org/ Member address: arch...@jab.org
