diff --git a/install.sh b/install.sh
index 9823fa4..acccb6b 100644
--- a/install.sh
+++ b/install.sh
@@ -5,8 +5,11 @@ print_ylw(){
 }
 
 print_ylw "[ ipv6 turn off ]"
-sysctl -w net.ipv6.conf.all.disable_ipv6=0
-sysctl -w net.ipv6.conf.default.disable_ipv6=0
+cat << EOF >> /etc/sysctl.conf
+net.ipv6.conf.all.disable_ipv6=0
+net.ipv6.conf.default.disable_ipv6=0
+net.ipv4.ip_forward=1
+EOF
 sysctl -p
 
 print_ylw "[ sshd_config backup ]"