How Email Clients Work

Just as web browsing software provides a graphical interface for navigating the World Wide Web, electronic mail (e-mail) software, often referred to as an e-mail "client," provides an easy-to-use interface for managing your e-mail messages.E-mail is the most-popular use of the Internet. Literally trillions of messages are sent worldwide in a single year. To participate in e-mail, you need a client. It can be standalone software, such as the popular Microsoft Outlook (http://www.microsoft.com/windows/oe) or Eudora (http://www.eudora.com). Or, it can even be a web-based client, such as the wildly popular free e-mail services offered by Yahoo! (http://www.yahoo.com) and MSN Hotmail (http://www.hotmail.com).

The basic features of all e-mail clients are just variations on a theme. After you have set up e-mail software and an e-mail account (and your own e-mail address), you can send, receive and forward messages; send and receive files attached to messages; and organize messages into folders and maintain a digital address book of names, e-mail address and other contact information.

Some clients offer more features than this, such as calendars, scheduling and sophisticated e-mail organizing and message blocking tools, but all e-mail software at its most basic lets you perform the tasks described above.

E-mail messages are transmitted from computer to computer using protocols built into the e-mail client and the e-mail servers that route messages to the proper recipients.

Here's what happens after you address an e-mail message, type its contents, then hit the Send button.

1. The digital e-mail message uses SMTP (Simple Mail Transfer Protocol) to communicate with a mail server. If you are a working in a home office and have an Internet connection subscription with an Internet service provider (ISP), the message is first sent via SMTP to your ISP's e-mail server.
2. The server, using Domain Name Server (DNS), determines who the recipient of the message should be and then uses SMTP to deliver the message to the e-mail server associated with the designated e-mail account. A failed delivery results in a message reporting the problem that's sent back to the e-mail's sender.
3. The recipient's e-mail client then uses either POP3 (Post Office Protocol 3) or IMAP (Internet Access Mail Protocol, which is gradually replacing the older POP3) to accept the message into the e-mail client from the recipients' e-mail server.



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