IMAP - Internet Message Access Protocol

An internet protocol used for the storage and management of email folders on a mail server (an IMAP server).

IMAP is different to POP3, in that your messages and mail folders are permanently stored on the server.

How does it work?

  • For sending and receiving email, IMAP is pretty much the same as normal POP3 email. You can still use Outlook, FireBird or your favourite email software.
  • When you first enable an IMAP mail account, you will notice a list of folders from the server appear in your mail client.
  • When you send an email, the mail is sent twice. Once to your SMTP server, and then once to the IMAP server so that it can be stored in the Sent Items folder.

Advantages over POP3

  • Synchronisation and WebMail. A copy of all mail folders reside on the mail server itself, so you can check your email from a WebMail system, your home or office PC, or your notebook computer. When you send an email, your mail folders are synchronized with the mail server, so the new email appears in the Sent Items of all your machines.
  • Mailbox Sharing. For example, a mailbox can be accessed by the entire sales team of your office. When someone replies to a customer, the message is marked as Reply-Sent in everyone's email software. When a message is sent, it appears in the Sent Items folder for all users of the mailbox.
  • Data Protection. A copy of all mail folders reside on the mail server, so loss or corruption of your local hard disk or computer does not effect your email storage. Additionally, most servers are typically backed up and protected with RAID drives and other backup systems, further protecting your email.


  • Storage Costs. Mail is stored on the server, so server-side storage space is required for each mailbox. This can be more expensive than simply downloading your new POP3 email to your local hard disk, as hosting costs are also involved. Depending on the size of the mail storage available, it might only be possible to store 1-3 years worth of email.
  • Learning Curve. It takes a little getting used to IMAP mail, if you are used to normal POP3 email (but the benefits far outweigh this learning time).

Which mail software can I use?

These days, most desktop and phone/tablet mail software supports IMAP by default, as well as POP3. The following mail clients are what most users use:
  • Outlook / Outlook Express
  • Evolution
  • FireBird
  • Eudora
  • IMAP WebMail systems
  • Android phones and tablets
  • iPhone/iPad(tm)

How much space do I need?

  • For most users, 1gb is around 2-4 years of email.
  • You can save space by deleting email that contains large attachments or large photos, after saving the attachment.

How can I collect my mail?

To collect your mail from an IMAP mail server, you will need:
  • IMAP mail server name (eg:
  • IMAP user name
  • IMAP password

See Also

  • POP3 - Post Office Protocol, the most commonly used protocol for collecting email

More Information

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