Philadelphia Reflections

SMTP Authorization and Handling Bounced Emails with PEAR Mail

Recently our ISP started requiring user sign on in order to send emails. PHP's mail function stopped working as a result.

Naturally, the ISP did not notify us of this change so we were quite surprised when many thousands of emails on our newsletter list were rejected (every one of them, in fact).

What error message was returned to us to notify us of what the problem was? Why this helpful note:

Mail sent by user nobody being discarded due to sender restrictions in WHM->Tweak Settings

Doesn't that just say it all?

I'm being snide, but our ISP is really quite good about keeping its software up to date and aside from an occasional surprise like this, they are very reliable. Being up to date including the automatic incorporation of the PEAR Mail facility which we are now using.

PEAR's Mail system works quite well but two problems were very vexing until we stumbled our way to a solution:

1. How, exactly, do we sign on to the SMTP server?
2. How do we ensure that bounced emails (the bane of all email lists) get returned to us?

You might not think that the first question would be so hard but it actually took a good deal of trial and error to get it right. As for the second question, there is an awful lot of wrong information available out in Internet land (including but not limited to VERP and XVERP which I advise you to avoid).

With PEAR Mail you first set up a "factory" and then send emails, either singly or in a loop. We keep the user id, password, etc. in a file "above" the web server in hopes that will keep them a secret ... here's the code (it actually is in production and it does in fact work):

<?php
include('Mail.php');

# the email constants are contained in a file outside the web server
include("/level1/level2/level3/constants.php");

$headers = array (
         'From' => '"name"<addr@domain.com>',
         'Sender' => '"name"<addr@domain.com>',
         'Reply-To' => '"name"<addr@domain.com>',
         'Return-Path' => 'addr@domain.com',
         'Content-type' => 'text/html; charset=iso-8859-1',
         'X-Mailer' => 'PHP/' . phpversion(),
         'Date' => date("D, j M Y H:i:s O",time()),
         'Content-Language' => 'en-us',
         'MIME-Version' => '1.0'
         );

// call the PEAR mail "factory"
$smtp = Mail::factory('smtp',
      array (
            'host' => EMAIL_HOST,
            'port' => EMAIL_PORT,
            'auth' => true,
            'username' => EMAIL_USERNAME,
            'password' => EMAIL_PASSWORD,
            'persist' => true,
            'debug' => false
            ), '-f addr@domain.com'
      );

# to send emails:
#
# $headers['To']      = $to;        # provide the "$to" variable, something like $to = '"name"<addr@domain.com>';
#                                   # note that the first parameter of $smtp->send can be "decorated" this way or just a naked email address
# $headers['Subject'] = $subject;   # provide the "$subject" variable
# $mail = $smtp->send($to, $headers, $contents_of_the_email);
#                          -------- ................................> except for 'To' and 'Subject',
#                                                                     $headers is provided by this module but can be over-ridden
# if (PEAR::isError($mail))
# {
#   echo "<p style='color:red;'>The email failed; debug information follows:<br />";
#   echo $mail->getDebugInfo() . "<br />";
#   echo $mail->getMessage()   . "</p>";
# }
# else
# {
#   echo "<p>email successfully sent</p>";
# }

?>

My thanks to https://htmlentities.net/ for the HTML entites conversion.

Originally published: Wednesday, February 27, 2013; most-recently modified: Wednesday, June 05, 2019