#!/bin/bash

iptables -F
iptables -A INPUT -p tcp --tcp-flags ALL NONE -j DROP
iptables -A INPUT -p tcp ! --syn -m state --state NEW -j DROP
iptables -A INPUT -p tcp --tcp-flags ALL ALL -j DROP
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 443 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 25 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 465 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 110 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 995 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 143 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 993 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 8080 -j ACCEPT -m comment --comment "Jenkins"
iptables -A INPUT -p tcp -m tcp --dport 8123 -j ACCEPT -m comment --comment "Dynmap"
iptables -A INPUT -p tcp -m tcp --dport 8192 -j ACCEPT -m comment --comment "Votifier"
iptables -A INPUT -p tcp -m tcp --dport 23000 -j ACCEPT -m comment --comment "WarmRoast"
iptables -A INPUT -p tcp -m tcp --dport 25565 -j ACCEPT -m comment --comment "Minecraft"
iptables -I INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P INPUT DROP
# do "iptables-save" manually because this makes rules persist after restart. If you do get locked out you can just restart your server and your old rules will load since you didn't save the new ones.