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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

Other TCP/IP Electronic Mail Access and Retrieval Methods 1 2 TCP/IP World Wide Web Electronic Mail Access

Pros and Cons of Direct Server E-Mail Access

These techniques are much more commonly associated with timesharing systems, which commonly use the UNIX family of operating systems than others. They are also often combined; for example, remote access is often provided for UNIX users, but most companies don't want users logging in directly to the SMTP server. Instead, an Internet service provider might run an SMTP server on one machine called “mail.companyname.com” and also operate a different server that is designed for client access called “users.companyname.com”. A user could access e-mail by dialing into the “users” machine, which would employ NFS to access user mailboxes on the “mail” machine.

Direct server access is a method that has been around for decades. At one time, this was how the majority of people accessed e-mail, for two main reasons. First, if you go back far enough, protocols like POP or IMAP had not yet been developed; the TCP/IP e-mail system as a whole predates them by many years and direct access was the only option back then. Second, the general way that e-mail and networks were used years ago was just different than it is today. Most individuals did not have PCs at home, and there was no Internet as we know it. Remotely accessing a UNIX server using a modem or Telnet for e-mail and other services was just “the way it was done”.

I myself got started using direct server access for e-mail over 10 years ago, and still use this today. I Telnet in to a client machine and use a UNIX e-mail program called elm to access and manipulate my mailbox. To me, this provides numerous advantages. First and most importantly, I can access my e-mail using Telnet from any machine on the Internet, anywhere around the world. Second, since I am logged in directly, I get immediate notification when new mail arrives, without having to routinely check for new mail. Third, my mailbox is always accessible and all my mail is always on a secure server in a professionally-managed data center. Fourth, I have complete control over my mailbox and can edit it, split it into folders, write custom “spam” filters, or do anything else I need to do.

This probably sounds good, but most people today do not use direct server access because of the disadvantages of this method. One big issue is that you must be logged in to the Internet to access your e-mail. Another one, perhaps even larger, is the need to be familiar with UNIX and a UNIX e-mail program. UNIX is simply not as “user-friendly” as a graphical operating systems such as Windows or the Apple Macintosh. For example, my UNIX e-mail program doesn't support color and cannot show me attached graphic images. I must extract images and other files from MIME messages and transfer them to my own PC for viewing.

Most people today don't know UNIX and don't want to know it. They are much happier using a fancy graphical e-mail program based on POP3 or IMAP4. However, there are still a number of us old UNIX dinosaurs around who feel the benefits of direct access outweigh the drawbacks. Oh, one other benefit that I forgot to mention is that it's very hard to get a virus in e-mail when you use UNIX.

Other TCP/IP Electronic Mail Access and Retrieval Methods 1 2 TCP/IP World Wide Web Electronic Mail Access