My iptables configuration script

firewall.sh

#!/bin/bash

setupAccept () {
  $1 -P INPUT ACCEPT
  $1 -P OUTPUT ACCEPT
  $1 --flush

  $1 -A INPUT -i lo -j ACCEPT
  $1 -A OUTPUT -o lo -j ACCEPT

  $1 -A INPUT -p tcp --dport 80 -j ACCEPT
  $1 -A INPUT -p tcp --dport 22 -j ACCEPT
  $1 -A INPUT -p tcp --dport 443 -j ACCEPT
  $1 -A INPUT -p udp --sport 53 -j ACCEPT
  $1 -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
  $1 -P INPUT DROP
}

setupAccept iptables
setupAccept ip6tables