I’m trying to move away from Google and replace my Gmail account. But reading about the different options, I’m realizing I don’t really understand email at all - e.g. the difference between the client and the domain name, the different protocols, encryption.
Does anyone have articles or books to suggest as a “Basics of Email: 101”? Thank you!
Good question, I don’t think I’m interested in hosting emails myself. The goal is likely going to be to choose a different provider. But that being said, I’m curious about what “hosting email” even means. The outcome I’m looking for is to be able to have enough understanding to compare different service providers and understand the differences between them.
The thing is, you don’t need to know anything for that. Things like pricing, storage amount, maybe anti spam measurements, maybe quality of the interface are much more important. The underlying technology is more or less irrelevant.
But let me try to give you a quick overview to hopefully sate your curiosity:
The server program to send and receive emails is called an SMTP (Simple Mail Transfer Protocol) server. It receives the mails sent from other company’s SMTP servers. The so called MX (Mail eXchange) entry in the domain system tells everyone where to find that server. Popular open source servers are Postfix, Exim and Sendmail.
If you have an email program (the email client) on your computer or smartphone it will log into the SMTP server and give it the mail you want to send. Popular email clients are Thunderbird, Outlook and I think the one on MacOS is just called Mail. If you are used to send your mail from the Gmail website that website is the email client.
SMTP does not give you anything to actually read the mails. That is usually done through an IMAP (Internet Message Access Protocol) server. Your client connects to the IMAP server to get a list of all your mail folders and the mails in there and whether they are marked as read, unread, important, etc. Usually the username and password for SMTP server and IMAP server are the same for convenience.
In terms of encryption your connection to these servers from the mail client and the connections between SMTP servers can be encrypted. But the mails themselves, ie what is stored on the server, are not encrypted.
There are some standards like GPG (GNU Privacy Guard) to encrypt mails but they are not very widespread. And most importantly they require sender and recipient of the mail to have the encryption set up. They encrypt the content of the mail but not the meta data like the sender and recipient, send date, ip addresses of sending and receiving SMTP servers, etc.
Hope that helps. Feel free to ask questions.