Perl for System Administration

Chapter 8. Electronic Mail

Unlike the other chapters in this book, this chapter does not discuss how to administer a particular service, technology, or knowledge domain. Instead, we’re going to look at how to use email from Perl as a tool for system administration.

Perl can help us in an administrative context with both sending and receiving email. Email is a great notification mechanism: often we want a program to tell us when something goes wrong, provide the results of an automatic process (like a late night cron or scheduler service job), or let us know when something we care about changes. We’ll explore how to send mail from Perl for these purposes and then look at some of the pitfalls associated with the practice of sending ourselves mail.

Similarly, we’ll look at how Perl can be used to post-process mail we receive to make it more useful to us. Perl can be useful for dealing with spam and managing user questions.

This chapter will assume that you already have a solid and reliable mail infrastructure. We’re also going to assume that your mail system, or one that you have access to, uses protocols that follow the IETF specifications for sending and receiving mail. The examples in this chapter will use protocols like SMTP (Simple Mail Transfer Protocol, RFC821) and expect messages to be RFC822-compliant. We’ll go over these terms in due course.

Sending Mail

Let’s talk about the mechanics of sending email first and then tackle the more sophisticated issues. The traditional (Unix) ...