#!/bin/bash


#### Clear ####

iptables -F
iptables -X

#++++++++++++++


#### Policy ####################

iptables -P INPUT   DROP
iptables -P FORWARD DROP
iptables -P OUTPUT  DROP

#+++++++++++++++++++++++++++++++


##### CUSTOM CHAINS ####################################################################

echo icmp
# Icmp
iptables -N ICMP
iptables -A ICMP -m limit --limit 15/minute -j LOG --log-prefix "Icmp: "
iptables -A ICMP -j DROP

echo bad flags
# Bad Flags, Bogus etc.
iptables -N BOGUS
iptables -A BOGUS -m limit --limit 15/minute -j LOG  --log-prefix "Bogus: "
iptables -A BOGUS -j DROP

echo lan spoof
# Lan Spoof
iptables -N LANSPOOF
iptables -A LANSPOOF -m limit --limit 15/minute -j LOG --log-prefix "LanSpoof: "
iptables -A LANSPOOF -j DROP

echo loopback spoof
# Loopback Spoof
iptables -N LOOPSPOOF
iptables -A LOOPSPOOF -m limit --limit 15/minute -j LOG --log-prefix "LoopSpoof: "
iptables -A LOOPSPOOF -j DROP

echo final firewall
# Finall Firewall
iptables -N FIREWALL
iptables -A FIREWALL -m limit --limit 15/minute -j LOG --log-prefix "Firewall: "
iptables -A FIREWALL -j DROP

#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


##### INPUT BLOCK ##############################################################################

# Drop all ICMP
iptables -A INPUT -p icmp -j ICMP

# LAN Spoof
iptables -A INPUT -i eth0 -s 192.168.1.0/24 -j LANSPOOF
iptables -A INPUT -i wlan0 -s 192.168.1.0/24 -j LANSPOOF

# Loopback Spoof
iptables -A INPUT ! -i lo -s 127.0.0.0/8 -j LOOPSPOOF

# Fragments
iptables -A INPUT -f -j BOGUS

# Bogus packets
iptables -A INPUT -m conntrack --ctstate INVALID -j BOGUS
iptables -A INPUT -p tcp --tcp-flags FIN,ACK FIN -j BOGUS
iptables -A INPUT -p tcp --tcp-flags ACK,PSH PSH -j BOGUS
iptables -A INPUT -p tcp --tcp-flags ACK,URG URG -j BOGUS
iptables -A INPUT -p tcp --tcp-flags SYN,FIN SYN,FIN -j BOGUS
iptables -A INPUT -p tcp --tcp-flags SYN,RST SYN,RST -j BOGUS
iptables -A INPUT -p tcp --tcp-flags FIN,RST FIN,RST -j BOGUS
iptables -A INPUT -p tcp --tcp-flags ALL ALL -j BOGUS
iptables -A INPUT -p tcp --tcp-flags ALL NONE -j BOGUS
iptables -A INPUT -p tcp --tcp-flags ALL FIN,PSH,URG -j BOGUS
iptables -A INPUT -p tcp --tcp-flags ALL SYN,FIN,PSH,URG -j BOGUS
iptables -A INPUT -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j BOGUS
iptables -A INPUT -m conntrack --ctstate NEW,RELATED -p tcp ! --tcp-flags ALL SYN -j BOGUS


#----- INPUT ACCEPT ----------------------------------------------------------------------------

# Already established and related
iptables -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

# Loopback
iptables -A INPUT -i lo -j ACCEPT

# allow sshing
iptables -A INPUT -p tcp --dport ssh -j ACCEPT

#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++



##### OUTPUT BLOCK #####################################################################

# Drop all ICMP
iptables -A OUTPUT -p icmp -j ICMP

# Bogus packets
iptables -A OUTPUT -m conntrack --ctstate INVALID -j BOGUS

#---- OUTPUT ACCEPT --------------------------------------------------------------------

# Loopback
iptables -A OUTPUT -o lo -j ACCEPT

# Dns
iptables -A OUTPUT -p udp --dport 53 -d 8.8.8.8 -j ACCEPT
iptables -A OUTPUT -p udp --dport 53 -d 8.8.8.8 -j ACCEPT

# Services
iptables -A OUTPUT -p tcp --dport 80 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 443 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 873 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 993 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 110 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 587 -j ACCEPT
# ssh
#iptables -A OUTPUT -p tcp --dport ssh -j ACCEPT
iptables -A OUTPUT -p tcp --sport ssh -j ACCEPT

#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++



##### FORWARD BLOCK ####################################################################

# Bogus Packets
iptables -A FORWARD -m conntrack --ctstate INVALID -j BOGUS

#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++



##### FINAL CATCH ALL ##########

iptables -A INPUT  -j FIREWALL
iptables -A OUTPUT -j FIREWALL

#+++++++++++++++++++++++++