If $CFG->smtphosts is empty, then mailer uses PHP mail() == sendmail.

diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index d6bf254e50419cfea5e7e1cb2d2836c014f14a5a..7b83b6dba19f3499f4eea64e193112b599a320cb 100644 (file)
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -909,8 +909,12 @@ function email_to_user($user, $from, $subject, $messagetext, $messagehtml="", $a
 
     $mail->Version = "Moodle";                         // mailer version 
     $mail->PluginDir = "$CFG->libdir/phpmailer/";      // plugin directory (eg smtp plugin)
-    $mail->IsSMTP();                                   // set mailer to use SMTP
-    $mail->Host = "$CFG->smtphosts";                   // specify main and backup servers
+    if ($CFG->smtphosts) {
+        $mail->IsSMTP();                                   // use SMTP directly
+        $mail->Host = "$CFG->smtphosts";                   // specify main and backup servers
+    } else {
+        $mail->IsMail();                                   // use PHP mail() = sendmail
+    }
 
     $mail->From     = "$from->email";
     $mail->FromName = "$from->firstname $from->lastname";