diff --git a/admin/process_email.php b/admin/process_email.php
new file mode 100755
index 00000000000..7604bb06e55
--- /dev/null
+++ b/admin/process_email.php
@@ -0,0 +1,79 @@
+#!/usr/bin/php -f
+<?
+define('FULLME','cron'); // prevent warnings
+//error_reporting(0);
+//ini_set('display_errors',0);
+require_once(dirname(dirname(__FILE__)).'/config.php');
+$tmp = explode('@',$_ENV['RECIPIENT']);
+$address = $tmp[0];
+
+// BOUNCE EMAILS TO NOREPLY
+if ($_ENV['RECIPIENT'] == $CFG->noreplyaddress) {
+    $user->email = $_ENV['SENDER'];
+
+    if (!validate_email($user->email)) {
+        die();
+    }
+    
+    $site = get_site();
+    $subject = get_string('noreplybouncesubject','moodle',$site->fullname);
+    $body = get_string('noreplybouncemessage','moodle',$site->fullname)."\n\n";
+    
+    $fd = fopen('php://stdin','r');
+    if ($fd) {
+        while(!feof($fd)) {
+            $body .=  fgets($fd);
+        }
+        fclose($fd);
+    }
+    
+    $user->id = 0; // to prevent anything annoying happening
+    
+    $from->firstname = null;
+    $from->lastname = null;
+    $from->email = '<>';
+    $from->maildisplay = true;
+    
+    email_to_user($user,$from,$subject,$body);
+    die ();
+}
+/// ALL OTHER PROCESSING
+// we need to split up the address
+$prefix = substr($address,0,4);
+$mod = substr($address,4,2);
+$modargs = substr($address,6,-16);
+$hash = substr($address,-16);
+
+if (substr(md5($prefix.$mod.$modargs.$CFG->sitesecret),0,16) != $hash) {
+	die("HASH DIDN'T MATCH!\n");
+}
+list(,$modid) = unpack('C',base64_decode($mod.'=='));
+
+if ($modid == '0') { // special
+    $modname = 'moodle';
+}
+else {
+    $modname = get_field("modules","name","id",$modid);
+    require_once('mod/'.$modname.'/lib.php');
+}
+$function = $modname.'_process_email';
+
+if (!function_exists($function)) {
+	die(); 
+}
+$fd = fopen('php://stdin','r');
+if (!$fd) {
+    exit();
+}
+
+while(!feof($fd)) {
+    $body .= fgets($fd);
+}
+
+$function($modargs,$body); 
+
+fclose($handle);
+
+
+
+?>
\ No newline at end of file
diff --git a/config-dist.php b/config-dist.php
index ccdefda0e6e..68bb3b5df91 100644
--- a/config-dist.php
+++ b/config-dist.php
@@ -195,6 +195,17 @@ $CFG->defaultblocks = 'participants,activity_modules,search_forums,admin,course_
 // may break things for users coming using proxies that change all the time,
 // like AOL.
 //      $CFG->tracksessionip = true;
+//
+//
+// The following lines are for handling email bounces.
+// $CFG->handlebounces = true;
+// $CFG->minbounces = 10;
+// $CFG->bounceratio = .20;
+// The next lines are needed both for bounce handling and any other email to module processing.
+// mailprefix must be EXACTLY four characters.
+// Uncomment and customise this block for Postfix 
+//$CFG->mailprefix = 'mdl+'; // + is postfix default separator. 
+//$CFG->maildomain = 'youremaildomain.com';
 
 //=========================================================================
 // ALL DONE!  To continue installation, visit your main page with a browser
diff --git a/lang/en/moodle.php b/lang/en/moodle.php
index 23fe5db34dd..c73934a24c8 100644
--- a/lang/en/moodle.php
+++ b/lang/en/moodle.php
@@ -810,6 +810,9 @@ $string['nopotentialadmins'] = 'No potential admins';
 $string['nopotentialcreators'] = 'No potential course creators';
 $string['nopotentialstudents'] = 'No potential students';
 $string['nopotentialteachers'] = 'No potential teachers';
+$string['noreplyname'] = 'Do not reply to this email';
+$string['noreplybouncemessage'] = 'You have replied to a no-reply email address. If you were atttempting to reply to a forum post, please instead reply using the $a forums. '."\n\n".'Following is the content of your email:'."\n\n";
+$string['noreplybouncesubject'] = '$a - bounced email.';
 $string['noresults'] = 'No results';
 $string['normal'] = 'Normal';
 $string['normalfilter'] = 'Normal search';
@@ -1042,6 +1045,7 @@ $string['timezone'] = 'Timezone';
 $string['to'] = 'To';
 $string['today'] = 'Today';
 $string['todaylogs'] = 'Today\'s logs';
+$string['toomanybounces'] = 'That email address has had too many bounces. You <b>must</b> change it to continue.';
 $string['toomanytoshow'] = 'There are too many users to show.';
 $string['top'] = 'Top';
 $string['topic'] = 'Topic';
diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index 36c00174415..70f69a85719 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -954,7 +954,6 @@ function require_login($courseid=0, $autologinguest=true) {
                    Please contact your Moodle Administrator.');
         }
     }
-
     // Check that the user account is properly set up
     if (user_not_fully_set_up($USER)) {
         redirect($CFG->wwwroot .'/user/edit.php?id='. $USER->id .'&amp;course='. SITEID);
@@ -1085,7 +1084,68 @@ function update_user_login_times() {
  * @return boolean
  */
 function user_not_fully_set_up($user) {
-    return ($user->username != 'guest' and (empty($user->firstname) or empty($user->lastname) or empty($user->email)));
+    return ($user->username != 'guest' and (empty($user->firstname) or empty($user->lastname) or empty($user->email) or over_bounce_threshold($user)));
+}
+
+function over_bounce_threshold($user) {
+    
+    global $CFG;
+    
+    if (empty($CFG->handlebounces)) {
+        return false;
+    }
+    // set sensible defaults
+    if (empty($CFG->minbounces)) {
+        $CFG->minbounces = 10;
+    }
+    if (empty($CFG->bounceratio)) {
+        $CFG->bounceratio = .20;
+    }
+    $bouncecount = 0;
+    $sendcount = 0;
+    if ($bounce = get_record('user_preferences','userid',$user->id,'name','email_bounce_count')) {
+        $bouncecount = $bounce->value;
+    }
+    if ($send = get_record('user_preferences','userid',$user->id,'name','email_send_count')) {
+        $sendcount = $send->value;
+    }
+    return ($bouncecount >= $CFG->minbounces && $bouncecount/$sendcount >= $CFG->bounceratio);
+}
+
+/** 
+ * @param $user - object containing an id
+ * @param $reset - will reset the count to 0
+ */
+function set_send_count($user,$reset=false) {
+    if ($pref = get_record('user_preferences','userid',$user->id,'name','email_send_count')) {	
+        $pref->value = (!empty($reset)) ? 0 : $pref->value+1;
+        update_record('user_preferences',$pref);
+    }
+    else if (!empty($reset)) { // if it's not there and we're resetting, don't bother.
+        // make a new one
+        $pref->name = 'email_send_count';
+        $pref->value = 1;
+        $pref->userid = $user->id;
+        insert_record('user_preferences',$pref);
+    }
+}
+
+/** 
+* @param $user - object containing an id
+ * @param $reset - will reset the count to 0
+ */
+function set_bounce_count($user,$reset=false) {
+    if ($pref = get_record('user_preferences','userid',$user->id,'name','email_bounce_count')) {	
+        $pref->value = (!empty($reset)) ? 0 : $pref->value+1;
+        update_record('user_preferences',$pref);
+    }
+    else if (!empty($reset)) { // if it's not there and we're resetting, don't bother.
+        // make a new one
+        $pref->name = 'email_bounce_count';
+        $pref->value = 1;
+        $pref->userid = $user->id;
+        insert_record('user_preferences',$pref);
+    }
 }
 
 /**
@@ -2635,8 +2695,37 @@ function setup_and_print_groups($course, $groupmode, $urlroot) {
     return $currentgroup;
 }
 
+function generate_email_processing_address($modid,$modargs) {
+    global $CFG;
+    
+    if (empty($CFG->sitesecret)) {
+        set_config('sitesecret',random_string(10));
+    }
+    
+    $header = $CFG->mailprefix . substr(base64_encode(pack('C',$modid)),0,2).$modargs;
+    return $header . substr(md5($header.$CFG->sitesecret),0,16).'@'.$CFG->maildomain;
+}
 
 
+function moodle_process_email($modargs,$body) {
+    // the first char should be an unencoded letter. We'll take this as an action
+    switch ($modargs{0}) {
+        case 'B': { // bounce
+            list(,$userid) = unpack('V',base64_decode(substr($modargs,1,8)));
+            if ($user = get_record_select("user","id=$userid","id,email")) {
+                // check the half md5 of their email
+                $md5check = substr(md5($user->email),0,16);
+                if ($md5check = substr($modargs, -16)) {
+                    set_bounce_count($user);
+                }
+                // else maybe they've already changed it?
+            }
+        }
+        break;
+        // maybe more later?
+    }
+}
+
 /// CORRESPONDENCE  ////////////////////////////////////////////////
 
 /**
@@ -2657,7 +2746,7 @@ function setup_and_print_groups($course, $groupmode, $urlroot) {
  * @return boolean|string Returns "true" if mail was sent OK, "emailstop" if email
  *          was blocked by user and "false" if there was another sort of error.
  */
-function email_to_user($user, $from, $subject, $messagetext, $messagehtml='', $attachment='', $attachname='', $usetrueaddress=true) {
+function email_to_user($user, $from, $subject, $messagetext, $messagehtml='', $attachment='', $attachname='', $usetrueaddress=true, $repyto='', $replytoname='') {
 
     global $CFG, $FULLME;
 
@@ -2675,6 +2764,11 @@ function email_to_user($user, $from, $subject, $messagetext, $messagehtml='', $a
     if (!empty($user->emailstop)) {
         return 'emailstop';
     }
+    
+    if (over_bounce_threshold($user)) {
+        error_log("User $user->id (".fullname($user).") is over bounce threshold! Not sending.");
+        return false;
+    }
 
     $mail = new phpmailer;
 
@@ -2709,7 +2803,14 @@ function email_to_user($user, $from, $subject, $messagetext, $messagehtml='', $a
 
     $adminuser = get_admin();
 
-    $mail->Sender   = $adminuser->email;
+    // make up an email address for handling bounces
+    if (!empty($CFG->handlebounces)) {
+        $modargs = 'B'.base64_encode(pack('V',$user->id)).substr(md5($user->email),0,16);
+        $mail->Sender = generate_email_processing_address(0,$modargs);
+    }
+    else {
+        $mail->Sender   = $adminuser->email;
+    } 
 
     if (is_string($from)) { // So we can pass whatever we want if there is need
         $mail->From     = $CFG->noreplyaddress;
@@ -2720,7 +2821,15 @@ function email_to_user($user, $from, $subject, $messagetext, $messagehtml='', $a
     } else {
         $mail->From     = $CFG->noreplyaddress;
         $mail->FromName = fullname($from);
+        if (empty($replyto)) {
+            $mail->AddReplyTo($CFG->noreplyaddress,get_string('noreplyname'));
+        }
     }
+        
+    if (!empty($replyto)) {
+        $mail->AddReplyTo($replyto,$replytoname);
+    }
+
     $mail->Subject  =  stripslashes($subject);
 
     $mail->AddAddress($user->email, fullname($user) );
@@ -2759,6 +2868,7 @@ function email_to_user($user, $from, $subject, $messagetext, $messagehtml='', $a
     }
 
     if ($mail->Send()) {
+        set_send_count($user);
         return true;
     } else {
         mtrace('ERROR: '. $mail->ErrorInfo);
diff --git a/user/edit.php b/user/edit.php
index 2305f463a7d..0f42ec34757 100644
--- a/user/edit.php
+++ b/user/edit.php
@@ -165,6 +165,11 @@
                     auth_user_update($userold, $usernew);
                 };
 
+                 if ($userold->email != $usernew->email) {
+                    set_bounce_count($usernew,true);
+                    set_send_count($usernew,true);
+                }
+
                 add_to_log($course->id, "user", "update", "view.php?id=$user->id&course=$course->id", "");
 
                 if ($user->id == $USER->id) {
@@ -193,6 +198,10 @@
     $strparticipants = get_string("participants");
     $strnewuser = get_string("newuser");
 
+    if (over_bounce_threshold($user) && empty($err['email'])) {
+        $err['email'] = get_string('toomanybounces');
+    }
+
     if (($user->firstname and $user->lastname) or $newaccount) {
         if ($newaccount) {
             $userfullname = $strnewuser;
@@ -307,6 +316,9 @@ function find_form_errors(&$user, &$usernew, &$err, &$um) {
     if (empty($usernew->email))
         $err["email"] = get_string("missingemail");
 
+    if (over_bounce_threshold($user) && $user->email == $usernew->email) 
+        $err['email'] = get_string('toomanybounces');
+
     if (empty($usernew->description) and !isadmin())
         $err["description"] = get_string("missingdescription");