diff --git a/lib/util/index.js b/lib/util/index.js
index <HASH>..<HASH> 100644
--- a/lib/util/index.js
+++ b/lib/util/index.js
@@ -538,8 +538,8 @@ var interfaceData = [hostname, os.platform(), os.release(),
 })();
 
 var clientId = crypto.createHmac('sha256', 'x-whistle-client-id')
-  .update(interfaceData.join('\r\n')).digest('hex')
-  + Math.floor(Math.random() * 1000000).toString(16);
+  .update(interfaceData.join('\r\n')).digest('hex');
+
 exports.setClientId = function(headers, enable) {
   if (enable && (enable.clientId || enable.clientID || enable.clientid)) {
     headers['x-whistle-client-id'] = clientId;
refactor: generate client id by os.networkInterfaces()