It's still easy to fake what shows up in a user's mail client. I see tons of spam and phishing sent with invalid information in the short headers, which is enou

It's still easy to fake what shows up in a user's mail client. I see tons of spam and phishing sent with invalid information in the short headers, which is enough to fool most people. The progress has been in mail servers/filtering that catch when validation checks fail so that ideally spammers aren't able to abuse a mail server in the first place, and when they do those messages don't reach people's mailbox (or if they do they hit the spam folder).