Enabling PHP mail() in Debian easily and quickly

I've run into a problem more than once where the mail() function in PHP didn't work. Unlike with a Windows deployment, you can't simply set an SMTP server in the php.ini file; you must set a value for the sendmail_path.

If you're running a mail server like Sendmail or Postfix alongside your web server, this is no big deal. But for the rest of us, do we really need a big beefy MTA just to mail-enable PHP?

No, we don't! I found a very simple way to get PHP sending mail without setting up a full-blown MTA, using sSMTP. sSMTP is not a running daemon, does not have a queue, and it cannot accept mail for delivery -- all it does is relay a message immediately and directly to the SMTP server it's configured to use. For most PHP users, this is a perfect solution.

1. First, install ssmtp
   

   apt-get install ssmtp

2. Next, edit the configuration file at /etc/ssmtp/ssmtp.conf.
   
   1. Set the mailhub= line to the name or address of your SMTP server
   2. Set the hostname= line to the actual host name of this server
   3. Set FromLineOverride=YES, otherwise, the From: set in any PHP application will be ignored
   4. If your SMTP server requires authentication, then
      
      • Set AuthUser= to the SMTP username
      • Set AuthPass= to the correspnding password
      • Set AuthMethod=LOGIN
3. Now you need to configure PHP. In Debian, it's recommended to create new .ini files inside of /etc/php5/conf.d instead of editing the php.ini file directly. Create a mail.ini file inside /etc/php5/conf.d, and add the following line:
   

     sendmail_path = /usr/sbin/ssmtp -t
   

   PHP requires the -t option, and the usual -i option is ignored

4. Save the mail.ini and restart Apache
   

   /etc/init.d/apache2 restart

Now, the mail() function should work as designed!