In most people’s on-line life, e-mail ranks right up there with the Web as an essential Internet application. From the client side, you need to be able to read e-mail messages and keep up to date on essential Internet humor and hoaxes. In addition, you want to be able to accept and open attachments–files enclosed with an e-mail message.
From the server side, you have several possibilities that you may need to support, depending on your cross-platform needs.
- You may want to deliver incoming e-mail to users, either via the Post Office Protocol version 3 (POP3) or Internet Mail Access Protocol (IMAP).
- You may want to send outgoing e-mail that is bound for addresses across the Internet via the Simple Mail Transfer Protocol (SMTP).
- You may want to manage mailing lists with a list server that accepts incoming messages and redistributes them to a list of subscriber e-mail addresses.
- You may want to automatically send files, as e-mail attachments, back to users who send e-mail requests. This is particularly useful if a significant chunk of your audience only has e-mail access (but not Web or FTP) to the Internet.
Maintaining the full spectrum of e-mail server functions can be a more time-consuming activity than providing Web (HTTP) and FTP services. In the following sections, I’ll discuss e-mail clients, introduce e-mail server functions, and provide some examples of list server and e-mail file server functions.
The Most Common E-mail Problem
In researching cross-platform difficulties for particular applications (see Chapter 6), I found that a common source of trouble was not with the applications themselves but with sharing the files as e-mail attachments.
When an e-mail client sends an attached file across the Internet, the software at both ends performs steps that aren’t visible to the user. Specifically, the attached file must first be "encoded" on the sender’s machine, and on the receiver’s machine the encoded file must be "decoded" so that the recipient can use it. The reason for encoding is that the e-mail protocols expect data in a certain form, and binary attachments are not in that form. The same limitation of the e-mail protocols often leads to problems in the translation of special characters such as curly quotes (" ") or accented letters (é, ü).
Problems arise because there are different types of encoding, which not all e-mail clients can decode. For example, Eudora Pro on the Mac can encode files as AppleDouble, AppleSingle, BinHex, and Uuencode data fork, as shown in Figure 5-10. (You can also change the encoding method for an individual message with the encoding button in the message window.)
I’ll give you two guesses to determine which two encoding methods you might use mainly for Mac recipients. On the other hand, Outlook Express 4.5 for the Mac cannot use AppleSingle, but it does understand AppleDouble, MIME (Base64), Uuencode, and BinHex. BinHex is more widely accepted, but if all else fails, you can use the older standard of Uuencoding. In contrast, the Windows version of Eudora permits encoding via MIME, BinHex, and Uuencode, while Outlook Express permits MIME and Uuencode.
The Mac Eudora settings window also points out another potential problem–the checkbox "Always send Macintosh information." Again, if you exchange files regularly with non-Mac users, you may want to disable this option so that Windows or UNIX clients aren’t confused by the information in the Mac file’s resource fork.
E-mail Clients
If you think you’re limited to Qualcomm’s Eudora Pro or Microsoft’s Outlook Express for your e-mail client, have a look at Table 5-8. And the list doesn’t include Claris Emailer, discontinued by Apple, but which you might find available for download, and which, according to persistent rumors, might be resurrected.
In practice, there are a few features that may help you decide which e-mail client best suits your needs.
POP3 or IMAP. You need to determine which protocol your e-mail provider supports, and select an e-mail client that can speak the appropriate protocol. With POP3, your e-mail software downloads all your e-mail messages from the server to your computer. You then read, reply, and save your messages on your Mac. You might set messages to remain on the server for several days, but for the most part, your e-mail is on your computer. With IMAP, on the other hand, your e-mail stays on the server, and you read, reply to, and save your messages on the server. The advantage of IMAP is that you can use any computer with an IMAP client and a network connection to read your e-mail. No matter where you are, your e-mail messages and folders will be there when you log in.
Password security. Your network administrator may choose a higher level of security than plain-text passwords for accessing your e-mail. For POP, you may need a client that supports Kerberos or APOP (authenticated POP) passwords. For IMAP, you may need a client that supports the secure sockets layer (SSL) used by secure Web forms.
Off-line features. If you have a dial-up connection to the Internet or use a laptop while you’re away from the network, you should look for an e-mail client that supports off-line reading, writing, and saving of e-mail. Most do. Some have additional features such as holding messages for delivery until the next time you go on-line.
Attachments. Since we are considering e-mail in terms of a cross-platform working environment, you want to be sure your e-mail client accepts and sends attached files. Again, most do. Extra features that you may want to look for include automatic compression of outgoing attachments.
Beyond these considerations, you should select an e-mail client that you feel comfortable using, ranging from the 500-kilobyte download of Musashi to the 5.5-megabyte PowerMail to the 10 megabyte Eudora Pro demo download. To get started with any client, you need the same basic set of configuration information, which is shown in Figure 5-11. The figure shows the e-mail settings panel from Internet Config, instead of a particular e-mail client. You need to know, at minimum:
- Your e-mail address, of the form username@your-company.com, to which other Internet users should direct their messages to you.
- Your e-mail account, the username on the server that stores your incoming e-mail. With POP accounts, the server often, but not always, has "pop" in the name. Your e-mail account may or may not be the same as your e-mail address.
- Your e-mail password.
- Your SMTP host, the name of the server that handles your outgoing mail. The SMTP server often has "smtp" in the name, but it can also be the same as the POP server. For example, post-office.your-company.com may handle both incoming and outgoing mail.