What to Do When You Need a Little POP in Your Network

What to Do When You Need a Little POP in Your Network

The last e-mail protocol I'll cover here is called Post Office Protocol (POP). The current version, POP3, also allows you to transfer e-mail, like SMTP. However, POP3 was designed specifically for use between an e-mail client and its e-mail server; it cannot transfer e-mail between servers.

Yes, POP3 essentially lets you do a subset of the functions of SMTP. So, why bother with another protocol when SMTP already allows clients to get their e-mail? Well, POP3 allows for several options for authentication, as well as some other useful features for e-mail clientsfeatures that are not included in SMTP.

One of POP3's better features is authentication. Authentication refers to the process of one device identifying itself to another device via a name and a password. The other device then decides whether the first device is allowed access. For instance, if you have an e-mail account through your ISP, at some point you were given an e-mail address and password. When you check your e-mail, if you use POP3 (and you probably do), your e-mail client identifies itself and provides a password. The e-mail server decides if you should be allowed to get the e-mail. Figure 8-7 outlines the process with POP3.