PHP 4通过SMTP发送电子邮件

Question

我有一个PHP 4代码，需要修改才能通过SMTP发送电子邮件，我已经在服务器上安装了Pear邮件包。它是Sevrer 2008 R2 64位。问题是它不发送任何电子邮件！我在这里缺少什么？Mail.php位于与实际网站文件不同的文件夹中，因此我必须在＆＃34; Include＆＃34;中指定路径。该文件的名称是Vistiro.php3：请建议：

Function PostSlip() {
    Global $_parent,$_contact,$_problem,$_summary;
    $p_contact = addslashes($_contact);
    $p_problem = addslashes($_problem);
    $p_summary = addslashes($_summary);
    $p_now          =   time();
    $qstring="insert into slips (spid,o_date,status,priority,o_tech,problem,summary,is_public,l_activity,l_tech,ctag) values ($_parent,$p_now,'O',4,'$p_contact','$p_problem','$p_summary','0','$p_now','$p_contact','ANONYMOUS')";   
    $qhandle = db_query($qstring);
    $count = db_affected_rows($qhandle);
    $newsid = db_insertid($qhandle);
    RecalcSlip($_parent);
    echo "<tr><td bgcolor=#808080 width=100% align=center>\n";
    if ($count > 0) {
        echo "Thank you for your submission.<br>";
        echo "Your Slip ID is <b>$newsid</b><br>";
        echo "Use this number at a later date to check on the status of this entry.";

        include "/inetpub/PHP_New/PEAR/Mail.php";
        $from = "username@domain.com";
        $to = "username@domain.com";
        $subject = "Test email using PHP SMTP with SSL\r\n\r\n";
        $body = "This is a test email message";

        $host = "smtp.companyname.com";
        $port = "25";
        $username = "domain\username";
        $password = "email password";

        $headers = array ('From' => $from,
          'To' => $to,
          'Subject' => $subject);
        $smtp = Mail::factory('smtp',
          array ('host' => $host,
            'port' => $port,
            'auth' => true,
            'username' => $username,
            'password' => $password));

        $mail = $smtp->send($to, $headers, $body);

        if (PEAR::isError($mail)) {
          echo("<p>" . $mail->getMessage() . "</p>");
        } else {
          echo("<p>Message successfully sent!</p>");
        }

    } else {
        echo "An error occured during the update.  Sorry, please try again later.";
    }
    echo "<br><a href=\"visitor.php3\">Return to Browsing</a>";
}