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IMAP

Hosting 4 min read Entry 26 of 78
Definition

IMAP is the way a mail app reads your email while leaving it on the server, so every device you own sees the same inbox.

In plain English

Read a message on your phone and it shows as read on your laptop. File it into a folder and the folder is there too. That is IMAP: the server holds the mail, and your apps are windows onto it.

The older alternative, POP, downloads mail to one device and often deletes it from the server, which is why an old setup can leave one computer holding everything.

Why it matters

Anyone with a phone and a computer needs their mail to agree with itself. IMAP is what makes that happen.

It also makes your mail recoverable. Lose the laptop and the mail is still on the server, because it never only lived on the laptop.

How it works

  1. The app connects to the serverWith your address, your password and the incoming server name.
  2. Folders are synchronisedThe structure on the server is mirrored in the app.
  3. Changes go both waysRead, moved, flagged or deleted is recorded on the server for every device.
  4. Sending uses SMTPA separate setting, which is why mail can arrive fine and still refuse to send.

Mailboxes have a size limit

Because everything stays on the server, a mailbox fills up. When it does, new mail bounces rather than arriving quietly. Archive or increase the quota before that happens.

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