diff --git a/UnitPay.php b/UnitPay.php
index d020b49..c1ef52a 100644
--- a/UnitPay.php
+++ b/UnitPay.php
@@ -66,6 +66,16 @@ private function getMd5sign($params)
         return md5(join(null, $params).$this->secretKey);
     }
 
+    /**
+     * Return IP address
+     *
+     * @return string
+     */
+    protected function getIp()
+    {
+        return $_SERVER['REMOTE_ADDR'];
+    }
+
     /**
      * Get URL for pay through the form
      *
@@ -145,7 +155,7 @@ public function api($method, $params = array())
      */
     public function checkHandlerRequest()
     {
-        $ip = $_SERVER['REMOTE_ADDR'];
+        $ip = $this->getIp();
         if (!isset($_GET['method'])) {
             throw new InvalidArgumentException('Method is null');
         }