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IMAP-Based Email--You Can Take it With You


Email 
Logo The email programs that are supported by C&C offer you the ability to read your email from various locations and computers.

In the campus-wide electronic mail (email) system at the University of Washington, your incoming email resides in a repository called an inbox. Email messages in your inbox are available to you from anywhere on the campus network, the worldwide Internet, or from your computer at home. This is possible because of something called the Interactive Mail Access Protocol or IMAP.

HOW IMAP WORKS

IMAP works on the principle of a client-server relationship, where one computer (the client) requests services from another computer (the server). In the campus email system, an IMAP- based email program such as Pine or Mailstrom is the client. It requests services from a computer called a--mail server--where your incoming mail messages reside.

For example, in Pine, when you open a remote mailbox and type I to see the Mail Index screen, Pine asks the mail server for a list of all the messages in your inbox. Information such as who sent you the message, the date it was sent, and the subject of the message is displayed for each message in the list. When you press V to view a message, Pine asks the mail server for the contents of that message.

Graphic of 
email system Although the new messages you view in PC-Pine or Mailstrom appear to be on the computer you are using, they actually reside in the inbox on the mail server. They are not on your computer until you save them.

Having your email delivered to a mail server is far more reliable than having it delivered to your desktop computer. While mail servers are always turned on, your desktop computer may not be. Any attempt to deliver email to your computer when it is turned off results in the email being delayed, and if your computer is off for too long (e.g., several days) the mail will be returned to the sender.

EASY ACCESS TO YOUR EMAIL

You can reach your inbox from your campus office or lab using various email programs on various computers. The rule is that you must use an IMAP-based email program on a computer that is connected to the campus network. It is possible, for example, to reach your inbox via PC-Pine on a PC, Mailstrom on a Macintosh computer, or EasyMail on a NeXT.

IMAP also lets you read your incoming email messages from anywhere on the Internet, including from your computer at home. However, until a campus-wide dialup IP facility is available, which would permit use of PC-Pine or Mailstrom from home or hotel, your dialup or remote mail access may require logging into a Uniform Access computer.

To view your messages, first dial in or use telnet to connect to your Uniform Access account, and then start Pine. The graphic above shows how you can reach your inbox on the IMAP mail server from different locations and different computers.

Since all IMAP-based mail programs can access the same inbox, any operation you perform on your inbox in one email program is reflected in your mail the next time you use another program. For example, if you delete a message from your inbox using PC-Pine in your office, the message will not be in your Pine inbox when you dial in to a C&C computer from home later that night.

GETTING IMAP

C&C offers IMAP servers on Unix Uniform Access computers. However, a campus department might want to operate its own IMAP server. The IMAP source code is available via anonymous FTP from ftp.cac.washington.edu in the /mail directory.

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University of Washington Computing & Communications
Windows on Computing, No. 13, May 1993
newsltr@cac.washington.edu