Unfortunately the latter need to be specifically compiled into the PHP installation which means they may not
be available for some users. In contrast Zend_Mail is a fairly complete implementation of mail functionality
that does not require any specific PHP configuration aside from the general requirements of the Zend
Framework itself.
We will start the chapter with some general information about how email actually works before going into
more detail about the construction of an email message with Zend_Mail. From there we will expand on your
practical knowledge by building a simple support tracker.
9.1 Background on email
Whenever I need to describe technology to clients I start by looking for comparable real world examples and
this is particularly appropriate when explaining email as it is actually modelled after the process of physical
mail. In the next section we will give an overview of how email works and at the same time demonstrate the
part Zend_Mail plays in the process.
9.1.1 Email simplified
Just as the complex routing process of physical mail can be reduced to simply dropping a letter in the mailbox
and waiting for it to arrive in the letterbox of its addressee, so it is with email, albeit many times faster. In the
following example, illustrated in figure 9.
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