Talking To Your Mailserver Is Not as Hard as You Think!
The technology behind E-Mails (or ‘emails‘) always interested me. This is because in some sense it was way ahead of its time by being a decentralized communication system. Unlike WhatsApp, Telegram or other messenger services, where the service provider has a centralized server (or nowadays a network of servers) processing all the messages; with emails, everybody can host their own mailserver to send and receive messages to everybody else. If Meta or Telegram decides to shut down their server, all communication is lost and the service cannot be used anymore. But with email, you can just move to another server (as long as you own your own domain at least).
One of the major components that power our modern email systems is the IMAP4 protocol. It is used to connect your email client to your mailserver. It’s the language used by the client to ask the server for the newest unread emails and the server responds with its contents. POP3 is (or was) also very popular and still widely supported but not used so much because it comes with a few drawbacks (a topic for another day). You probably have heard about SMTP as well, and this is the protocol that is used to send emails.
But those protocols alone don’t allow us to send emails. Emails heavily rely on other technologies like Domains, DNS, IPv4, SPF, DKIM, DMARC, SSL/TLS, S/MIME, PGP, NTP. In general, Emails are not too different from websites as they share a lot of the same technology (and nowadays you can even send HTML emails).
