Comment by petcat
4 days ago
> Why I cannot send email from my self-hosted, no dns, servers to gmail?
Because email is a cesspool ruined by spammers and Google is doing the only sensible thing they can to block the scams and pill ads from reaching their users inboxes.
You did truncate the context: you have to add email addresses with IP literals. This does change everything.
google is more than anything else (and this has been a few years) following its agenda at making email just a private garden of messaging with a few "chosen ones" of his friends (selection based on $$$). They are presuming de facto anybody who does not fit their technical agenda to be a spammer. This is the same with their "web" with their web engines from the 'whatwg cartel'.
An IP/domain becomes a source of spam until it does. And with their billions of $$$, I guess they have an army of guys to handle that properly: trying hard enough to notify the owner with data, etc. Yes, this is 99% of the work which has to be done at gmail.