title: Why does PHP mail() require a mail program like sendmail/postfix/etc. for sending emails?
body: <p>Why does the PHP <code>mail()</code> function require a mail program like sendmail/postfix/etc. for sending emails?</p>
  
  <p>I ask because sending email is a client action and not something that needs to run a server.</p>
  
  <p>What is so complicated about creating a native PHP mail function without the need to install a sendmail/postfix/etc. program that has excessive functionality as a server that can get requests and not just send email as a client?</p>