diff --git a/library/Director/PropertyModifier/PropertyModifierGetHostByAddr.php b/library/Director/PropertyModifier/PropertyModifierGetHostByAddr.php
index 11adb4f4..eda66d1a 100644
--- a/library/Director/PropertyModifier/PropertyModifierGetHostByAddr.php
+++ b/library/Director/PropertyModifier/PropertyModifierGetHostByAddr.php
@@ -29,7 +29,10 @@ class PropertyModifierGetHostByAddr extends PropertyModifierHook
 
     public function transform($value)
     {
-        $host = gethostbyaddr($value);
+	if ($value === null) {
+	     return null;
+	}
+	$host = gethostbyaddr($value);
         if ($host === false) {
             switch ($this->getSetting('on_failure')) {
                 case 'null':