> If I get email from alice@example.tld, then I now know it's from example.tld. If the mail is spam, I can ask example.tld to block alice, or I can simply black

> If I get email from alice@example.tld, then I now know it's from example.tld. If the mail is spam, I can ask example.tld to block alice, or I can simply blacklist example.tld. Is this better than graylist+whitelist? Is it better than content based filtering? I'm not convinced. Is it better than requiring tls with valid cert for smtp? I can't see how. Rather than all this mess, I think I'd prefer we start at tls/ssl required for smtp...