diff --git a/uncloud/hack/hackcloud/mac-gen.py b/uncloud/hack/hackcloud/mac-gen.py
old mode 100644
new mode 100755
index f2a5db0..e2b4bc5
--- a/uncloud/hack/hackcloud/mac-gen.py
+++ b/uncloud/hack/hackcloud/mac-gen.py
@@ -36,7 +36,8 @@ class Mac(object):
     def __init__(self):
         self.base_dir = "."
 
-        self._prefix = "02:00"
+        self.prefix = 0x002000000000
+        #self.prefix = "{:012x}".format(self._prefix)
 
         self.free    = self.read_file("mac-free")
         self.last    = self.read_file("mac-last")
@@ -53,6 +54,11 @@ class Mac(object):
 
         return ret
 
+    def append_to_file(self, text, filename):
+        fname = os.path.join(self.base_dir, filename)
+        with open(fname, "a+") as fd:
+            fd.write("{}\n".format(text))
+
     @staticmethod
     def validate_mac(mac):
         if not re.match(r'([0-9A-F]{2}[-:]){5}[0-9A-F]{2}$', mac, re.I):
@@ -62,30 +68,24 @@ class Mac(object):
         if mac in self.free:
             raise Error("Mac already in free database: %s" % mac)
 
-        self._init_base_dir()
-        self.free.append(mac)
+        self.append_to_file(mac, "mac-free")
+        self.free    = self.read_file("mac-free")
+
 
     @staticmethod
-    def get_base_dir():
-        return cinv.get_base_dir("db/mac")
+    def int_to_mac(number):
+        b = number.to_bytes(6, byteorder="big")
+        return ':'.join(format(s, '02x') for s in b)
 
-    @classmethod
-    def exists(cls):
-        return os.path.exists(cls.get_base_dir())
+    def getnext(self):
+#        if self.free:
+#            return self.free.pop()
 
-    def get_next(self):
-        self._init_base_dir()
-
-        if self.free:
-            return self.free.pop()
-
-        if not self.prefix:
-            raise Error("Cannot generate address without prefix - use prefix-set")
+#        if not self.prefix:
+#            raise Error("Cannot generate address without prefix - use prefix-set")
 
         if self.last:
-            suffix = re.search(r'([0-9A-F]{2}[-:]){2}[0-9A-F]{2}$', self.last, re.I)
-            last_number_hex = "0x%s" % suffix.group().replace(":", "")
-            last_number = int(last_number_hex, 16)
+            last_number = int(self.last[0], 16)
 
             if last_number == int('0xffffff', 16):
                 raise Error("Exhausted all possible mac addresses - try to free some")
@@ -94,60 +94,16 @@ class Mac(object):
         else:
             next_number = 0
 
-        next_number_hex = "%0.6x" % next_number
-        next_suffix = "%s:%s:%s" % (next_number_hex[0:2], next_number_hex[2:4], next_number_hex[4:6])
+        next_number_string = "{:012x}".format(next_number)
 
-        next_mac = "%s:%s" % (self.prefix, next_suffix)
+        next_mac_number = self.prefix + next_number
+        next_mac = self.int_to_mac(next_mac_number)
 
-        self.last = next_mac
+        with open(os.path.join(self.base_dir, "mac-last"), "w+") as fd:
+            fd.write("{}\n".format(next_number_string))
 
         return next_mac
 
-
-    @property
-    def prefix(self):
-        return self._prefix
-
-    @prefix.setter
-    def prefix(self, prefix):
-        if not re.match(r'([0-9A-F]{2}[-:]){2}[0-9A-F]{2}$', prefix, re.I):
-            raise Error("Wrong mac address format - use 00:11:22")
-
-        self._init_base_dir()
-        self._prefix = prefix
-
-    @classmethod
-    def commandline_generate(cls, args):
-        mac = Mac()
-        print(mac.get_next())
-
-    @classmethod
-    def commandline_free_add(cls, args):
-        mac = Mac()
-        mac.validate_mac(args.address)
-        mac.free_append(args.address)
-
-    @classmethod
-    def commandline_free_list(cls, args):
-        mac = Mac()
-        for mac in mac.free:
-            print(mac)
-
-    @classmethod
-    def commandline_prefix_set(cls, args):
-        mac = Mac()
-        mac.prefix = args.prefix
-
-    @classmethod
-    def commandline_prefix_get(cls, args):
-        mac = cls()
-        print(mac.prefix)
-
-    @classmethod
-    def commandline_add(cls, args):
-        host = cls(fqdn=args.fqdn)
-        host.host_type = args.type
-
     @classmethod
     def commandline(cls):
         pass
@@ -156,4 +112,6 @@ class Mac(object):
 if __name__ == '__main__':
     m = Mac()
     m.commandline()
-    print(m.free)
+    # print(m.free)
+    #print(m.last)
+    print(m.getnext())
diff --git a/uncloud/hack/hackcloud/mac-last b/uncloud/hack/hackcloud/mac-last
new file mode 100644
index 0000000..df32b47
--- /dev/null
+++ b/uncloud/hack/hackcloud/mac-last
@@ -0,0 +1 @@
+000000000006