Email is a 1980s design that still runs the internet, and here's why
A Bit about Email
A walkthrough of how an email actually travels: from the sender's MUA through the MSA, MTA, and LDA to the recipient's inbox. The piece explains why the store-and-forward design exists (1980s servers were flaky and expensive), shows a live SMTP session with Postfix, and then digs into the authentication stack — SPF, DKIM, and reverse DNS — that big-tech uses to block spam, and why it locks out anyone sending from a residential connection.
If you don't like it, find a mail provider with more permissive rules: the only reason big-tech is able to keep the racket running is that five or so companies control 99% of communications.