diff --git a/shadowsocks-libev.sh b/shadowsocks-libev.sh
index f4f8f03..f152e40 100644
--- a/shadowsocks-libev.sh
+++ b/shadowsocks-libev.sh
@@ -169,9 +169,10 @@ function iptables_set(){
     echo "iptables start setting..."
     /sbin/service iptables status 1>/dev/null 2>&1
     if [ $? -eq 0 ]; then
-        /etc/init.d/iptables status | grep '${shadowsocksport}' | grep 'ACCEPT' >/dev/null 2>&1
+        /sbin/iptables -L -n | grep '${shadowsocksport}' | grep 'ACCEPT' >/dev/null 2>&1
         if [ $? -ne 0 ]; then
             /sbin/iptables -I INPUT -m state --state NEW -m tcp -p tcp --dport ${shadowsocksport} -j ACCEPT
+            /sbin/iptables -I INPUT -m state --state NEW -m udp -p udp --dport ${shadowsocksport} -j ACCEPT
             /etc/init.d/iptables save
             /etc/init.d/iptables restart
         else
@@ -277,10 +278,10 @@ function install_shadowsocks_libev(){
     pre_install
     download_files
     config_shadowsocks
-    if ! centosversion 7; then
+    install
+    if centosversion 6; then
         iptables_set
     fi
-    install
 }
 
 # Initialization step