diff --git a/CHANGES b/CHANGES
index 8c7bfc5..05bda56 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,9 @@
+3.1.1 2017-03-25
+- add "New session ticket"
+- ignore bind 10.0.0.0/8 and 192.168.0.0/16 by default
+- improve rand size under auth_aes128_*
+- fix bugs
+
 3.1.0 2017-03-16
 - add "glzjinmod" interface
 - rate limit
diff --git a/shadowsocks/obfsplugin/auth.py b/shadowsocks/obfsplugin/auth.py
index 83be824..ad2fbf8 100755
--- a/shadowsocks/obfsplugin/auth.py
+++ b/shadowsocks/obfsplugin/auth.py
@@ -1186,7 +1186,7 @@ class auth_aes128_sha1(auth_base):
         self.server_info.data.set_max_client(max_client)
 
     def rnd_data_len(self, buf_size, full_buf_size):
-        if buf_size > 1300 or self.last_rnd_len > 1300 or full_buf_size > 1492:
+        if buf_size > 1300 or self.last_rnd_len > 1300 or full_buf_size >= self.server_info.buffer_size:
             return 0
         if buf_size > 1100:
             return common.ord(os.urandom(1)[0]) % 128
diff --git a/shadowsocks/tcprelay.py b/shadowsocks/tcprelay.py
index 7f0523a..7f01f71 100644
--- a/shadowsocks/tcprelay.py
+++ b/shadowsocks/tcprelay.py
@@ -184,6 +184,7 @@ class TCPRelayHandler(object):
         server_info.key = self._encryptor.cipher_key
         server_info.head_len = 30
         server_info.tcp_mss = 1448
+        server_info.buffer_size = BUF_SIZE
         self._protocol.set_server_info(server_info)
 
         self._redir_list = config.get('redirect', ["*#0.0.0.0:0"])
diff --git a/shadowsocks/udprelay.py b/shadowsocks/udprelay.py
index 3dd7760..3d8df3b 100644
--- a/shadowsocks/udprelay.py
+++ b/shadowsocks/udprelay.py
@@ -928,6 +928,7 @@ class UDPRelay(object):
         server_info.key = encrypt.encrypt_key(self._password, self._method)
         server_info.head_len = 30
         server_info.tcp_mss = 1440
+        server_info.buffer_size = BUF_SIZE
         self._protocol.set_server_info(server_info)
 
         self._sockets = set()
diff --git a/shadowsocks/version.py b/shadowsocks/version.py
index 5ff56da..eed0e4e 100644
--- a/shadowsocks/version.py
+++ b/shadowsocks/version.py
@@ -16,5 +16,5 @@
 # under the License.
 
 def version():
-    return '3.1.0 2017-03-16'
+    return '3.1.1 2017-03-25'