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The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  TCP/IP Key Applications and Application Protocols            9  TCP/IP File and Message Transfer Applications and Protocols (FTP, TFTP, Electronic Mail, USENET, HTTP/WWW, Gopher)                 9  TCP/IP Electronic Mail System: Concepts and Protocols (RFC 822, MIME, SMTP, POP3, IMAP)                      9  TCP/IP Electronic Mail Access and Retrieval Protocols and Methods                           9  Other TCP/IP Electronic Mail Access and Retrieval Methods

TCP/IP Direct Server Electronic Mail Access 1 2 Usenet (Network News) and the TCP/IP Network News Transfer Protocol (NNTP)

Pros and Cons of Web-Based E-Mail Access

The big difference between Web-based mail and the UNIX methods is that the former is much easier for non-experts to use. Since the idea was first developed, many companies have jumped on the Web-mail bandwagon, and the number of people using this technique has exploded into the millions in just a few years. Many free services even popped up in the late 1990s as part of the “dot com bubble”, allowing any Internet user to send and receive e-mail using the Web at no charge (except perhaps for tolerating advertising). Many Internet Service Providers (ISPs) now offer Web access as an option in additional to conventional POP/IMAP access, which is useful for those who travel. Google’s new Gmail service is the latest entrant into the sweepstakes, offering users 1 GB of e-mail storage in exchange for viewing Google’s text ads on their site.

There are drawbacks to the technique, however, which as you might imagine are directly related to its advantages. Web-based mail is easy to use, but inflexible; the user does not have direct access to his or her mailbox, and can only use whatever features the provider's Web site implements. For example, suppose the user wants to search for a particular string in his or her mailbox; this requires that the Web interface provide this function. If it doesn't, the user is out of luck.

Web-based mail also has a disadvantage that is an issue for some people: performance. Using conventional UNIX direct access, it is easy to quickly read through a mailbox; the same is true of access using POP3, once the mail is downloaded. In contrast, Web-based mail services mean each request requires another HTTP request/response cycle. The fact that many Web-based services are free often means server overload that exacerbates the speed issue.

Note that when Web-based mail is combined with other methods such as POP3, care must be taken to avoid strange results. If the Web interface doesn't provide all the features of the conventional e-mail client, certain changes made by the client may not show up when Web-based access is used. Also, mail retrieval using POP3 by default removes the mail from the server. If you use POP3 to read your mailbox and then later try to use the Web to access those messages from elsewhere, you will find that the mail is “gone”—it's on the client machine where you used the POP3 client. Many e-mail client programs now allow you to specify that you want the mail left on the server after retrieving it using POP3.

TCP/IP Direct Server Electronic Mail Access 1 2 Usenet (Network News) and the TCP/IP Network News Transfer Protocol (NNTP)