POP v. IMAP

At Northwestern, you can access your e-mail with either POP or IMAP.

Note: Users who switch to IMAP (or back to POP from IMAP) should be cautioned that they must configure all their e-mail clients to use the same protocol to avoid e-mail corruption. For example, if you have IMAP configured for WebMail, then the same protocol configuration must be used by your other e-mail clients, such as Eudora.

What is POP? By default, Northwestern's e-mail system uses POP (Post Office Protocol) to access mail. With POP, your mail is saved for you in your mailbox on the server. When you read your mail with an application such as Eudora or Microsoft Outlook, it is downloaded to your computer and no longer kept on the server (unless you have selected the "Leave mail on server" option in your e-mail application). You should use POP if:

• you use POP now and are satisfied with it;
• you generally work with your e-mail only in a single location or on a single computer;
• WebMail works fine for you when you need to check new e-mail if you are not at the computer you normally use;
• messages you save are stored safely, with adequate backup protection, on your e-mail computer.

What is IMAP? IMAP (Internet Message Access Protocol), on the other hand, allows you to store all or part of your mail on the server. IMAP allows you to create and manipulate folders or mailboxes on the server, search for messages or keywords, or delete messages. You can view just the heading and the sender of the message and then decide whether to download it. Your messages and folders are available to you regardless of what computer you use to read your mail. Both Eudora and Microsoft Outlook/Express can use IMAP to read mail; WebMail can also use this setting. You may want to switch to IMAP if:

• you do a great deal of traveling and use WebMail as your main mail client;
• you need access to your new and old mail at multiple locations, e.g., office, lab, home;
• you use POP with the "leave e-mail on server" option. IMAP handles this more efficiently, especially as the Inbox gets larger.

If you are certain you want to switch to IMAP, first Set up IMAP Access on your e-mail server, then read and follow the appropriate configuration instructions for your e-mail software on the E-mail Configuration Web site.

A caveat about switching from IMAP to POP: If you switch from IMAP to POP, you will not be able to access any messages stored in folders other than the Inbox. Any messages in the Inbox are backed up at 2:00 a.m. each night to protect against server failure for both POP and IMAP users. See the backup restoral page for more information on restoring mail from these backups. IMAP folders created by the user are not backed up. Also, any Eudora filters or Outlook rules you created which move messages into your IMAP folders will be broken. For details about switching to or from IMAP and POP, visit the E-mail Configuration Web site.

A special note for faculty: If you have chosen IMAP, find out how to purchase additional folder space on the e-mail servers.

IMAP folders created by the user on the NU e-mail servers are not backed up by NUIT. It is the responsibility of each individual user to manage and back up mail folders that he/she creates. If you use IMAP, you should ensure that you have other copies of your mail for safekeeping.

About leaving mail on the server: Keep in mind that your IMAP inbox space and folder space are both limited. NUIT has established quotas for e-mail saved on servers. We do not recommend leaving read and unread mail on the server indefinitely, because you could easily exceed your mail quota. Instead, you should download mail you want to keep to your own computer, and delete unwanted mail.

NUIT Support Center

Central helpdesk for faculty, staff, and students.
847-491-HELP (4357)
consultant@northwestern.edu