POP and IMAP - What's It All About?

POP (Post Office Protocol) and IMAP (Internet Message AccessProtocol) are the protocols (rules) that email clients use to access and manage email. When you configure your email client, you will determine whether it will use POP or IMAP. Queen's ITServices offers support for both the POP and IMAP protocol.

Apple Mail, Outlook, Outlook Express, and WebMail are the most popular email clients that are used for sending and receiving email at Queen's. Of these, WebMail is the only one that is limited to using the IMAP protocol. Apple Mail, Outlook, and Outlook Express (and most other clients) can be configured to use either POP or IMAP. These protocols are not specific to the operating system (Windows, Mac OS, etc.).

 

Note KGH/HDH users:  IMAP is not available on the KGH/HDH Networks, only POP configurations will work.

What is the difference between POP and IMAP?

The key difference is that POP downloads your email to folders on your personal computer and IMAP keeps your email on the server and gives you access to all your folders (inbox, sent, etc.) on the server from multiple computers or webmail interface.

Note: When you configure your email client to use POP you can also choose to leave mail on the server. If you choose this option a copy of your email will be left on the server. This option is useful if you check your email in multiple locations. However, your email is still being managed on your personal computer.

The Mail Server

No matter what method you use to access your email, it all comes into Queen’s the same way. Your email arrives from somewhere in the world and lands on one of the campus mail servers. The University provides and supports email accounts for all Faculty, Staff, and Students on the Queen's Email server (mail.queensu.ca).

Note: Some departments have also chosen to provide their own email servers. If you have questions about a departmentally operated email server, please contact the department directly.

Once on the server, your messages are stored in the your inbox. Your email will remain in your inbox until you use some method to access it and move it to another location. This “some method” can be Apple Mail, Outlook, Outlook Express, WebMail or some other email client. "Another location" can be on your personal computer, folders you create on the server, or the trash. Your inbox has a diskquota. If you exceed your diskquota you will no longer be able to receive email. You will receive notifications from the server when you get close to exceeding your disquota.

When Apple Mail, Outlook, Outlook Express, or another email client are used, they have to be setup to use either POP or IMAP. WebMail uses IMAP by default.  NotifyLink requires you to use IMAP for all computers.

POP(Post Office Protocol)

POP is a mail retrieval method. It moves your email from the email server to your personal computer. You can then manage your email on your computer (ie. read your email, move email to different mailboxes or folders, delete your email, reply to email, send new email, etc.).

When there is the requirement to access your email from more than one location, for example you check your email at work and from home, you can configure your email client to "leave mail on server". This will leave a copy of your email on the server. This copy of your email will stay in the Inbox until it is moved. When you choose to "leave mail on server" it is also recommend you choose a time limit. Then, after the time has expired the copy of the email will be removed from the server. This only applies to email that has already been moved to your computer. The time limit does not apply to email you that has not been downloaded to your computer. This option is discussed in the Email Configuration documentation.

Using POP your email is stored on your personal computer.

POP notes:

• If you access your email from multiple locations/computers it is recommend you use IMAP.  If you prefer to use POP you will need to configure each computer to ensure your incoming mail is left on the server and email sent from one computer will not be accessible from another computer.
• Sent Mail is not accessible from WebMail.
• The folder structure you create for storing your email within a POP client will not be reflected on WebMail.
• If you use NotifyLInk to access your email through your Blackberry (or other supported smart phone) your email must be configured for IMAP. 

IMAP (Internet Message Access Protocol)

IMAP is a method of viewing and managing your email on the email server. Your email client is configured to access the mail server and you manage your email on the mail server. You read your email, send your email, move your email, delete your email, etc., all on the email server. IMAP does not move your email to your personal computer; your email stays on the server.

Since all your email (email you receive and copies of email you send) is being stored on the sever you must be much more aware of your diskquota.

When you are using IMAP you will have two sets of folders: Local Folders and Server Folders. Local Folders reside on the personal computer you are using. If you use multiple computers (work and home) you can have different local folders. Local Folders can be used to archive email to prevent exceeding your diskquota. Server Folders are located on the server so they are the same no matter where you view your email. Sever folders are not stored on your personal computer.

The big advantage with IMAP is that you can view and deal with all your email from work, from home, or from an internet café anywhere in the world. Queen's provides a WebMail that can be accessed through the internet. However, you can also configure Apple Mail, Outlook, Outlook Express, (and most email clients) to use IMAP.

IMAP notes:

• You have to get used to the two sets of folders, the Local Folders which are specific to every computer and the IMAP Server folders which are the same no matter where you look at them.
• NotifyLink requires you to use IMAP for Email client on all computers.
• Disk space on the server is limited. You need to manage your server folders. The IN mailbox must be cleaned out regularly.
• WebMail: When using the web to access your email, IMAP is assumed; the folder structure should look identical to that of your IMAP client whether it is Eudora, Outlook, Outlook Express, or some other email client.

 

IMAP and Folders

The folders seen when using an IMAP configured email client are the same folders seen when using WebMail. They are on the email server. Email can be moved to and from them or deleted.

If you create a folder in an IMAP configured email client that folder is automatically created on the server. If you use WebMail, you will see that new folder.

Note: If a user is using an IMAP configured email client and create folders in the IMAP Server Folders called work and home, the folders will show up on either computer if both computers are configured to use IMAP correctly.  The Home and Work folders will show up in the IMAP Server Folders list, they will even show up in WebMail. A correct configuration is key to getting this to work.

Note: Sent email will go into your local Sent Items folder unless you use Web Mail to send it. Copies of your sent email will be on the computer used to send the email.