> Maybe I'm mistaken, but I've read that some blacklists operate on the guilty until proven innocent basis and owner needs to prove that he is legit first, to e

> Maybe I'm mistaken, but I've read that some blacklists operate on the guilty until proven innocent basis and owner needs to prove that he is legit first, to each blocklist separately. No, I don't know of any public blocklists that operate that way. The big providers (msft & goog) have reputation mechanisms though, which can be volatile for a new domain. Getting that reputation to a hard blacklist requires that you genuinely spam, but some early mails may end up in junk folders anyway. > Would I need to learn and do all this if want to use custom domain with some provider like Protonmail or Fastmail? No. Your provider will give you instructions on how to set up your DNS records. The last relevant standard is from 2015, it's somewhat unlikely that you'll have to update these things often. Your provider should tell you if anything needs updating.