--- Net/DNS2/Socket.php
+++ Net/DNS2/Socket.php
@@ -129,7 +129,7 @@ class Net_DNS2_Socket
         //
         // bind to a local IP/port if it's set
         //
-        if (strlen($this->local_host) > 0) {
+        if (strlen((string)$this->local_host) > 0) {
 
             $opts['socket']['bindto'] = $this->local_host;
             if ($this->local_port > 0) {