16.2.1. The smail Mail Transport Agent

But take heart: even though patches are applied and features are added, your same old smail configuration files almost always continue to work just fine. You usually only need to update your binaries to stay up to date.

That's the good news. The bad news is that different distributions of smail install the files in different places. If you grab a set of binaries from an FTP site and install it over your obsolete installation, you might find that you have one version of smail installed in /usr/bin and another in /sbin. Because smail functions, as a number of mail utilities do, through the use of file links, this kind of inconsistency can cause real problems with your installation.

If you build a distribution from scratch, though, you may find that it is a generic installation not tailored for Linux. (However, a generic Unix FTP site is likely to have the full set of documentation that seems to be missing from some of the Linux sites we've checked.)

What can you do? Well, if you take a distribution from a particular FTP site, it might help to stick with that site, even if it means you don't get the latest and greatest update at the earliest possible moment. This works particularly well if the site is a binary distribution site--your configuration files will be left untouched. Or you can just jump in and install updated files and then use find or whereis to sort out tangled up links and duplicated files. In any case, you will likely find that even if your Linux installation script installed and configured smail correctly on your system, you don't like all the selected behaviors. If this is the case, often your best bet is to simply edit the smail configuration file for your system.

16.2.2. Getting the Mail to Your Computer with Fetchmail

If your provider stores your mail for you until you fetch it, and you do not want to use your mailer to download the mail, you need a program that retrieves the mail from your provider's computer. There are a lot of programs for doing this; we will discuss fetchmail here briefly, because it is both robust and flexible and can handle both POP3 and IMAP.

You can get fetchmail from your friendly Linux archive; chances are that your distribution carries it, too. In case you download a source distribution of fetchmail, unpack, build, and install it according to the installation instructions.

You can control fetchmail 's behavior both via command-line options or by a configuration file. It is a good idea to first try to fetch your mail by passing the necessary information on the command line, and when this works, to write the configuration file.

As an example, let's assume that my provider is running the POP3 protocol, that my username there is joeuser and that my password is secret. The hostname of the machine where the POP3 server is running is mail.isp.com. I can then retrieve my mail with the following command:

fetchmail --protocol POP3 --username joeuser mail.isp.com

fetchmail then asks me for my password, and after I specify it correctly, retrieves the mail waiting for me and passes it on to my MTA for further delivery. This assumes that a SMTP server is running on port 25 of my machine, but this should be the case if I have set up my MTA correctly.

While you are experimenting with fetchmail, it might be a good idea to also specify the option --keep. This prevents fetchmail from deleting the messages from your POP3 account. Normally, all messages are deleted from your provider's hard disk once they are safely stored on your own machine. This is a good thing, because most providers limit the amount of mail you can store on their machines before retrieving them, and if you don't delete the messages after fetching them, you might reach this limit quite soon. On the other hand, while testing, it is a good idea to be on the safe side and use --keep so as not to lose any mail.

With the options just shown to fetchmail, you should already be able to get your mail in most cases. For example, if your provider uses the newer IMAP protocol, simply specify IMAP in the command line instead of POP3. If your provider has some unusual setup, you might need one of the other options that the fetchmail manual page tells you about.

Once you are satisfied with the download process, you can write a fetchmail configuration file in order not to have to enter all the options each time you use the command. This configuration file is called .fetchmailrc and should reside in your home directory. Once you are done editing it, make sure it has the permission value 0600 so that nobody except yourself can read it, because this file might contain your password:

chmod 0600 ~/.fetchmailrc

The full syntax of the configuration file is detailed in the fetchmail man page, but in general you need only very simple lines that start with poll. To specify the same data as on the command line in the previous example, but this time include the password, put the following line into your configuration file:

poll mail.isp.com protocol pop3 username joeuser password secret

Now you can run fetchmail without any parameters. Since fetchmail already knows about your password from the configuration file, it will not prompt you for it this time. If you want to play safe while testing, add the word keep to the poll line.

Using fetchmail with a configuration file has one additional advantage: You can fetch mail from as many mailboxes as you want. Just add more poll lines to your .fetchmailrc, and fetchmail happily retrieves your mail from one server after the other.

When and how you run fetchmail depends on what kind of connection to the Internet you have. If you have a permanent connection or a cheap, flat rate, you might want to have fetchmail invoked by cron at a suitable interval (like once an hour). However, if your Internet connection is nonpermanent (dial-up) and costly, you might want to choose to run fetchmail by hand whenever you actually want to fetch and read your mail so as to minimize your Internet connection time. Finally, if you are using PPP for dialing in to your Internet service provider, you might want to invoke fetchmail from the ip-up script, which is invoked as soon as an Internet connection is made. With this setup, when you browse a web page and your computer dials up your provider, your mail is fetched automatically.

16.2.3. Other Email Administrative Issues

16.2.4. Installing Elm

The Elm mailer was created by Dave Taylor, of the Elm Development Group, and continues to be developed through the Usenet Community Trust. Copyrights on Elm are held by Dave Taylor and the Usenet Community Trust.

Elm isn't the most powerful mailer available, but it is robust and suits the needs of most users. It has a simple user interface with menus and built-in help. Most other screen-oriented mailers available on Linux support much the same basic mailer features, using a similar display interface. Once you know Elm, you can easily switch to another mailer if you find one more to your taste. Other popular text-mode mailers are pine and mutt; the supporters of the different mailers can start arguments that are no less violent than those between Emacs supporters and vi lovers. In addition, there are now also a great number of X-based GUI mailers that are often easier to set up and use than the traditional text-mode mailers like Elm. We will cover one of them, Netscape Messenger, later in this chapter.

In this discussion, we mention different directories and files that Elm uses. These are defaults; the mail administrator can set up some different locations, and each Elm user can change the setup of files and directories.

16.2.5. Using Netscape Messenger

Many people criticize Netscape Messenger for being slow and for missing some features. But on the other hand, Messenger is easy to set up and has some nice features like hierarchical folders and tight integration with the web browser.

Once you have installed Netscape Communicator, you can run the web browser Netscape Navigator as usual and then open up the Messenger window by selecting Messenger from the Communicator menu or by pressing the key combination Alt-2.

Figure 16-13. Netscape Messenger window

Before you can first use Messenger, you have to set up some things first. Select Edit from the Preferences menu and then open the configuration group Mail & Newsgroups by clicking on the little arrow next to it. You have to fill out at least the Identity and Mail Servers forms. First click on Identity and enter your name and email address as indicated in the dialog box.

Next, click on Mail Servers. The upper half of the dialog box shows a list of mail servers that Messenger should retrieve mail from. Unfortunately, even though there is a whole list provided here, you can have only one mail server unless you use the IMAP protocol.

To configure an Incoming Mail Server, click on the Add... button and fill out the form that appears. Your system administrator or your Internet provider will be able to give you all the data you need. Note that you can choose between three server types. For POP3 and IMAP, you will have to specify your username and password as they appear on your provider's server in addition to protocol-specific parameters. If you use one of those two server types, you do not need an MTA on your machine; Messenger automatically retrieves the mail and sorts the messages into your mail folders without any other programs intervening.

The option movemail, on the other hand, is used when you have set up other software like the MTA smail and the mail-fetching program fetchmail, both described earlier in this chapter. In this case, those programs will retrieve your mail and put them into your mail folder somewhere on your system, often /var/spool/mail/username. In this case, tell Messenger where movemail should pick up your mail from.

The next thing to set up is the outgoing mail server. If you have set up your own SMTP server because you have installed an MTA, enter either localhost (if the SMTP is running on the same machine as Messenger) or the hostname of the machine the SMTP server is running on. On the other hand, if you want to send outgoing mail directly to your provider, enter the hostname of your provider's SMTP server here. Depending on your provider, you might also need to specify your account name here again.

Once you are done with the configuration, you can tell Messenger to get your mail from wherever you specified and sort it into your folders. This is done by either clicking the Get Msg toolbar button or selecting File/Get New Messages from the File menu. If you get your mail from a POP3 or IMAP server, Messenger will first ask you for your password and then fetch your mail. All messages will be put into the Inbox folder where you can read them, store them into other folders, or simply delete them. How messages are dealt with is quite intuitive. You will be able to guess most of the functionality from the user interface. But when you are in doubt, you can always use the Help menu which, when you select an entry, opens a browser window (or reuses an already existing one) and shows the documentation on Netscape's web server.

To write a mail message, press Alt-M, click on the New Msg toolbar button, or select Message/New Message from the Message menu. Messenger opens a form where you can enter the recipients, the subject and, of course, the text of your mail.

Once you are done editing your mail you can press Alt-Enter, click on the Send toolbar button, or select Send Now from the File menu of the composition window. Messenger then directly contacts the SMTP server that you have configured and tries to send your mail. Of course, if you are using your provider's SMTP server, this requires that you are connected to your provider at that time or that you have configured your computer or gateway to dial out on demand.

If you have configured Messenger to use your provider's SMTP server and you have only a dial-up connection to the Internet, you might want to use another nifty feature of Messenger: if you send your mail by pressing Alt-Shift-Enter or selecting Send Later from the composition window's File menu, the message is not directly sent out, but instead stored in the Unsent Messages folder. You can collect your messages there until you have opened an Internet collection and then send them all at once by choosing Send Unsent Messages from the File menu. This is especially useful if dialing up to the Internet is costly where you live, because you can save yourself a lot of connection time.

We have only scratched the surface of what Messenger can do, and you might want to experiment further with it. A fairly basic thing to try out is to create new folders by selecting New Subfolder... from the File menu and then have Messenger sort your incoming messages automatically into the folders by subject, sender, or a number of other criteria. Sorting is accomplished by a feature called filters, which you can configure by selecting Message Filters... from the Edit menu.