| >, and I tend to be unsure how bad it actually is: sometimes it does seem pretty bad, other times it sounds like it's fine, and possibly the chatter about failed deliveries is caused by misconfigured servers and/or misunderstandings. It's not just misconfigured email server settings like DKIM, SPF, DMARC etc. One can correctly set all of those and still have the outgoing emails rejected or spamholed. Why? Because the big email players like GMail, Microsoft Outlook.com, etc use black-box heuristics of reputation datapoints that exist outside the boundaries of email settings such as... "amount of email volume", "# of spam abuse reports from ip block", etc. Because "sender reputation" cannot be encoded into an email configuration (DKIM/SPF/DMARC/etc), that's why nobody can provide a convenient Docker container with a perfectly working self-hosted email server that can reliably send email. If such a thing existed, the spammers would use it as well! A datapoint such as "volume of email from this ip" is an unstated behavior/activity number and not an identity setting like DKIM. And the invisible heuristics keep changing which causes previous email setups that worked -- to later stop working for no obvious reason. Why? Because there's a constant arms race between spammers and email filter algorithms. This means others' email spam heuristics that keep evolving and that you don't control -- blocks your self-hosted outbound emails without warning. That's why you have example of skilled admins who know what they're doing and had a working self-hosted setup for years suddenly getting their emails rejected:
https://www.tablix.org/~avian/blog/archives/2019/04/google_i... As to the contradicting anecdotes about the difficulties of self-hosting email, the issue is that the conversation shares the same unstated environments in comments about Uber or umbrellas that affects how the writer perceives the truth or relevance of their anecdote. - "The problems of self-hosted email getting blocked is overstated. I've been doing it and it's working fine." - "I'm not sure what value Uber provides. Taxi services have smartphone apps." - "I'm not sure why people use umbrellas. Every time I walk outside, it's not raining." As an example of evangelists and advice-givers not noticing their unstated environments...
Back in October 2017, a commenter (lucb1e) argued[1] that I was exaggerating the difficulties of reliably sending email but a year later in 2019, he eventually confirmed the same difficulties! [2] [1] https://news.ycombinator.com/item?id=15525505 [2] https://news.ycombinator.com/item?id=19757607 |
I've had this discussion on HN before. It's gotten to the point where I've had to have my clients and their corporate lawyers go to bat against mail providers to maintain deliverability. No mail provider has any interest whatsoever in allowing an independent mailserver to continue delivering now.
So far, legal threats have worked when push came to shove against certain networks. But I imagine the difficulty is only going to increase.