diff --git a/lib/datalib.php b/lib/datalib.php
index e242df05519..18ddf5005c7 100644
--- a/lib/datalib.php
+++ b/lib/datalib.php
@@ -2007,9 +2007,6 @@ function add_to_log($courseid, $module, $action, $url='', $info='', $cm=0, $user
     }
 
     $REMOTE_ADDR = getremoteaddr();
-    if (empty($REMOTE_ADDR)) {
-        $REMOTE_ADDR = '0.0.0.0';
-    }
 
     $timenow = time();
     $info = $info;
diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index dad6b677f18..16980c85b79 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -2526,8 +2526,8 @@ function require_user_key_login($script, $instance=null) {
     }
 
     if ($key->iprestriction) {
-        $remoteaddr = getremoteaddr();
-        if ($remoteaddr == '' or !address_in_subnet($remoteaddr, $key->iprestriction)) {
+        $remoteaddr = getremoteaddr(null);
+        if (empty($remoteaddr) or !address_in_subnet($remoteaddr, $key->iprestriction)) {
             print_error('ipmismatch');
         }
     }
@@ -8552,6 +8552,9 @@ function make_unique_id_code($extra='') {
  */
 function address_in_subnet($addr, $subnetstr) {
 
+    if ($addr == '0.0.0.0') {
+        return false;
+    }
     $subnets = explode(',', $subnetstr);
     $found = false;
     $addr = trim($addr);
@@ -8813,7 +8816,7 @@ function cleardoubleslashes ($path) {
  */
 function remoteip_in_list($list){
     $inlist = false;
-    $client_ip = getremoteaddr();
+    $client_ip = getremoteaddr(null);
 
     if(!$client_ip){
         // ensure access on cli
@@ -8835,9 +8838,10 @@ function remoteip_in_list($list){
  * Returns most reliable client address
  *
  * @global object
+ * @param string $default If an address can't be determined, then return this
  * @return string The remote IP address
  */
-function getremoteaddr() {
+function getremoteaddr($default='0.0.0.0') {
     global $CFG;
 
     if (empty($CFG->getremoteaddrconf)) {
@@ -8849,18 +8853,21 @@ function getremoteaddr() {
     }
     if (!($variablestoskip & GETREMOTEADDR_SKIP_HTTP_CLIENT_IP)) {
         if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
-            return cleanremoteaddr($_SERVER['HTTP_CLIENT_IP']);
+            $address = cleanremoteaddr($_SERVER['HTTP_CLIENT_IP']);
+            return $address ? $address : $default;
         }
     }
     if (!($variablestoskip & GETREMOTEADDR_SKIP_HTTP_X_FORWARDED_FOR)) {
         if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
-            return cleanremoteaddr($_SERVER['HTTP_X_FORWARDED_FOR']);
+            $address = cleanremoteaddr($_SERVER['HTTP_X_FORWARDED_FOR']);
+            return $address ? $address : $default;
         }
     }
     if (!empty($_SERVER['REMOTE_ADDR'])) {
-        return cleanremoteaddr($_SERVER['REMOTE_ADDR']);
+        $address = cleanremoteaddr($_SERVER['REMOTE_ADDR']);
+        return $address ? $address : $default;
     } else {
-        return null;
+        return $default;
     }
 }
 
diff --git a/mod/chat/lib.php b/mod/chat/lib.php
index ed9b6ced47c..0409dbb6f0b 100644
--- a/mod/chat/lib.php
+++ b/mod/chat/lib.php
@@ -601,9 +601,6 @@ function chat_login_user($chatid, $version, $groupid, $course) {
         // or provide a dummy value for the db
         if (empty($chatuser->ip)) {
             $chatuser->ip = getremoteaddr();
-            if (empty($chatuser->ip)) {
-                $chatuser->ip = '';
-            }
         }
 
         if (($chatuser->course != $course->id) or ($chatuser->userid != $USER->id)) {
@@ -628,9 +625,6 @@ function chat_login_user($chatid, $version, $groupid, $course) {
         // or provide a dummy value for the db
         if (empty($chatuser->ip)) {
             $chatuser->ip = getremoteaddr();
-            if (empty($chatuser->ip)) {
-                $chatuser->ip = '';
-            }
         }
 
 
diff --git a/mod/quiz/simpletest/testaccessrules.php b/mod/quiz/simpletest/testaccessrules.php
index 12448defa12..dbcb5d22eda 100644
--- a/mod/quiz/simpletest/testaccessrules.php
+++ b/mod/quiz/simpletest/testaccessrules.php
@@ -50,7 +50,7 @@ class simple_rules_test extends UnitTestCase {
 
         // Test the allowed case by getting the user's IP address. However, this
         // does not always work, for example using the mac install package on my laptop.
-        $quiz->subnet = getremoteaddr();
+        $quiz->subnet = getremoteaddr(null);
         if (!empty($quiz->subnet)) {
             $quiz->questions = '';
             $quizobj = new quiz($quiz, $cm, null);