diff --git a/server_pool.py b/server_pool.py
index 4b4663c..002ddfe 100644
--- a/server_pool.py
+++ b/server_pool.py
@@ -52,6 +52,9 @@ class ServerPool(object):
 		self.config = shell.get_config(False)
 		shell.print_shadowsocks()
 		self.dns_resolver = asyncdns.DNSResolver()
+		if not self.config.get('dns_ipv6', False):
+			asyncdns.IPV6_CONNECTION_SUPPORT = False
+
 		self.mgr = asyncmgr.ServerMgr()
 
 		self.tcp_servers_pool = {}
diff --git a/shadowsocks/obfsplugin/verify.py b/shadowsocks/obfsplugin/verify.py
index 1c939ae..5c54c78 100644
--- a/shadowsocks/obfsplugin/verify.py
+++ b/shadowsocks/obfsplugin/verify.py
@@ -332,7 +332,7 @@ class verify_sha1(verify_base):
             if sha1data != self.recv_buf[head_size:head_size + 10]:
                 logging.error('server_post_decrype data uncorrect auth HMAC-SHA1')
                 return b'E'
-            out_buf = to_bytes(chr(ord(self.recv_buf[0]) & 0xF)) + self.recv_buf[1:head_size]
+            out_buf = to_bytes(chr(ord(self.recv_buf[0]) & 0xEF)) + self.recv_buf[1:head_size]
             self.recv_buf = self.recv_buf[head_size + 10:]
             self.has_recv_header = True
         while len(self.recv_buf) > 2:
@@ -345,7 +345,7 @@ class verify_sha1(verify_base):
             if sha1data != self.recv_buf[2:12]:
                 raise Exception('server_post_decrype data uncorrect chunk HMAC-SHA1')
 
-            self.recv_id += 1
+            self.recv_id = (self.recv_id + 1) & 0xFFFFFFFF
             out_buf += data
             self.recv_buf = self.recv_buf[length:]