diff --git a/shadowsocks/asyncdns.py b/shadowsocks/asyncdns.py
new file mode 100644
index 0000000..a75be90
--- /dev/null
+++ b/shadowsocks/asyncdns.py
@@ -0,0 +1,73 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# Copyright (c) 2014 clowwindy
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+import socket
+import struct
+import common
+
+
+_request_count = 1
+
+# rfc1035
+#                                 1  1  1  1  1  1
+#   0  1  2  3  4  5  6  7  8  9  0  1  2  3  4  5
+# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+# |                      ID                       |
+# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+# |QR|   Opcode  |AA|TC|RD|RA|   Z    |   RCODE   |
+# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+# |                    QDCOUNT                    |
+# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+# |                    ANCOUNT                    |
+# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+# |                    NSCOUNT                    |
+# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+# |                    ARCOUNT                    |
+# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+
+
+def pack_request(address):
+    global _request_count
+    _request_count += 1
+    header = struct.pack('!HBBHHHH', _request_count, 1, 0, 1, 0, 0, 0)
+    pass
+
+
+def unpack_response(data):
+    # TODO detect address type
+    pass
+
+
+def resolve(address, callback):
+    callback(address)
+
+
+def test():
+    def _callback(address):
+        print address
+
+    resolve('www.baidu.com', _callback)
+
+
+if __name__ == '__main__':
+    test()