This is my firewall restoration script.

restore_firewall.sh

#!/bin/bash

iptables -F # Flush all!
iptables -X # Delete all custom chains!
iptables -t nat -F
iptables -t nat -X
iptables -t mangle -F
iptables -t mangle -X
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT

iptables -A INPUT -i lo -j ACCEPT # Accept all from the loopback interface
iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT # Accept established connections

# SSH and HTTP
iptables -A INPUT -p tcp --dport ssh -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
#iptables -A INPUT -p tcp --dport 8080 -j ACCEPT

# Ping
iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
iptables -A OUTPUT -p icmp --icmp-type echo-reply -j ACCEPT

# Drop everything else
iptables -A INPUT -j DROP