diff --git a/inc/init.php b/inc/init.php
index f642c8dcf3122e1aea7d560a834b198b4003885b..d84c5a232d67024f342d7e54baf584ae50c8ec05 100644
--- a/inc/init.php
+++ b/inc/init.php
@@ -144,8 +144,8 @@
   if(!defined('DOKU_LF')) define ('DOKU_LF',"\n");
   if(!defined('DOKU_TAB')) define ('DOKU_TAB',"\t");
 
-  // define cookie and session id
-  if (!defined('DOKU_COOKIE')) define('DOKU_COOKIE', 'DW'.md5(DOKU_REL));
+  // define cookie and session id, append server port when securecookie is configured FS#1664
+  if (!defined('DOKU_COOKIE')) define('DOKU_COOKIE', 'DW'.md5(DOKU_REL.(($conf['securecookie'])?$_SERVER['SERVER_PORT']:'')));
 
   // define Plugin dir
   if(!defined('DOKU_PLUGIN'))  define('DOKU_PLUGIN',DOKU_INC.'lib/plugins/');