Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.
Outgoing email is sent using the Simple Mail Transfer Protocol (SMTP). Fortunately, PHP’s built-in mail() function handles all SMTP socket-level protocols and handshaking for you. The mail() function acts as your mail client, sending email messages just as Outlook or Thunderbird might.
Before you can use PHP as a mail client, you must edit PHP’s configuration file, php.ini, to point PHP to the mail server’s location. For example, the script in Example 15-1 shows the section of php.ini that configures PHP to work with sendmail, the Unix mail server on many networks.