Sending Mail with SMTP and PHP
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.
Configuring PHP to Send Mail
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 Listing 16-1 shows the section of php.ini that configures PHP to work with sendmail, the Unix mail server on many networks.
[mail function] ; For Win32 only. SMTP = localhost ; For Win32 only. ;sendmail_from = firstname.lastname@example.org ; For Unix only. You may ...