How to prevent an IP leak on an asus n66u using merlin wrt?

[M0rph2020 5]

I've been trying to figure out where I need to insert these rules.

 

#!/bin/sh
iptables -I FORWARD -i br0 -o tun0 -j ACCEPT
iptables -I FORWARD -i tun0 -o br0 -j ACCEPT
iptables -I FORWARD -i br0 -o vlan2 -j DROP
iptables -I INPUT -i tun0 -j REJECT
iptables -t nat -A POSTROUTING -o tun0 -j MASQUERADE

 

On my router I used WINScp to create a firewall-start file on the /jffs directory but this script didnt work for some reason whenever I turn off the VPN my internet reverts back to clear net which I want to prevent. Am I even creating the right file? Is it supposed to be in the firewall-start file or another file. I've seen another user ask about this but their wasn't a reply. Thanks for the help.