Drupal SMTP Authentication with PEAR::Mail

If you want to use smtp authentication with Drupal you can use PEAR::Mail with drupal_mail_wrapper.

1. Install PEAR::Mail. On linux you can just run the following command as root:
   

    pear install --alldeps Mail

   
   


2. Create a new file, say includes/smtpmail/smtpmail.inc and paste the following code into it:
   

   
   <?php
   require_once 'Mail.php';
   require_once 'PEAR.php';
   
   function drupal_mail_wrapper($mailkey, $to, $subject, $body, $from, $headers) {
     global $smtpmail;
   
     $headers['From']    = $from;
     if ( empty($headers['To'])) {
       $headers['To'] = $to;
     }
     $headers['Subject'] = $subject;
   
     $recipients = $to;
     $mail_object =&Mail::factory('smtp', $smtpmail);
     $output = $mail_object->send($recipients, $headers, $body);
     return $output;
   }
   

   
   


3. Edit your settings.php and add the following at the end:
   

   
   $conf = array(
     'smtp_library' => 'includes/smtpmail/smtpmail.inc'
   );
   global $smtpmail;
   $smtpmail= array();
   $smtpmail["host"]  = 'your.mail.host';
   $smtpmail["auth"] = TRUE;
   $smtpmail["username"] = 'your_user_name';
   $smtpmail["password"] = 'your_password';
   

   
   

From now on every call to drupal_mail will go through your drupal_mail_wrapper and will be sent using PEAR::Mail with SMPT authentication.

I'm sure some more serious drupaler would have made this a nice module, with configuration screens and the lot, but I'm too lazy today.

"The system cannot execute the specified program" Error

You are trying to run some program on Windows (such as apache.exe or htpasswd.exe) and you are getting "The system cannot execute the specified program" error. This usually means that the program you are trying to run was compiled against DLLs that are not on your system. You should use Dependency Walker to see which DLLs are missing, and then install them.

The Apache 2.x binary windows distribution, specifically, was compiled against the Visual Studio 2005 re-distributable package, which you can download from microsoft.

Further reading (1) and (2)

Edit (Nov 2011):
Following this comment (by Annonymous) please note that you may need to download and use the 2008 package and not the 2005 one: The official download for the Microsoft Visual C++ 2008 SP1 Redistributable Package (x86) or The official download for the Microsoft Visual C++ 2008 Redistributable Package (x64)