How email works: why a fake email from your boss can reach your inbox
SMTP: how an email travels from mail server to mail server
An email never goes straight from your phone to your friend's. Who carries it, how do they talk, and why is it not lost when her phone is off?
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1
When Rono taps Send, the email does not go to you. It goes to a mail server: a computer that is always on, and whose job is to send and receive email.
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2
Most people send through the mail server of a big email provider, and those let you send only from your own address. So Rono rents a server of his own, and it sends whatever he writes.
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3
His server passes the email on to the mail server of the workshop, the one that takes in every email for woodshop.example. The two servers talk in a language made for this one job: SMTP, the Simple Mail Transfer Protocol.
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4
SMTP is a short chat in plain words. One server says who the email is for, the other agrees, the email goes over, and the other confirms. From that moment, the email is the job of the workshop's server.
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5
Each server keeps the email until the next one says it has it. If the workshop's server is down, the sending server holds on and tries again, for up to several days. You and the person you write to never have to be online at the same moment.
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6
The workshop's server puts the email in your mailbox, a folder it keeps for you. When your phone's email app asks for anything new, it gets a copy, and there it is on your screen.
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One step is missing. Rono's server had only your address to go on, and the part after the @ is a name, not a place. Among all the computers of the internet, it still found the right one.
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Quick check
Quick check.
Show the answer
No. Her mail server takes it and keeps it in her mailbox. Her phone gets it when it is on again and asks.
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Go further
Two names you may meet.