diff --git a/mininet/util.py b/mininet/util.py
index 6c7b426..673d3f6 100644
--- a/mininet/util.py
+++ b/mininet/util.py
@@ -253,10 +253,7 @@ def macColonHex( mac ):
     """Generate MAC colon-hex string from unsigned int.
        mac: MAC address as unsigned int
        returns: macStr MAC colon-hex string"""
-    if mac < 2 ** 24:
-        return 'A4:23:05:' + _colonHex( mac, 3 )
-    else:
-        return 'A4:23:05:' + _colonHex( mac, 3 )
+       return _colonHex( mac, 6 )
 
 def ipStr( ip ):
     """Generate IP address string from an unsigned int.