Script for loading and reloading iptables

iptables_conf.sh

#!/bin/bash

# Script to configure Linux' iptables and ip6tables
# setting the specified ports open and closing the rest.
# Optionally enables Fail2Ban on IPv4 (as the latest
# stables version [0.9.5] does not support it yet).

# The MIT License (MIT)
# Copyright (c) 2013-2016 Juma7C9
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy of this software
# and associated documentation files (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copiesor substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
# PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
# FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

IPv6_Enabled="True"
SSH_on_IPv4="True"
Fail2Ban_Enabled="True"

tcpPorts=( )
udpPorts=( )

bannedIPs=( )

if [ "${IPv6_Enabled}" == "True" ]
then
        tables=( iptables ip6tables )
else
        tables=( iptables )
fi

# Stop Fail2Ban
service fail2ban stop

for iptables in "${tables[@]}"
do
        "${iptables}" -P INPUT ACCEPT
        "${iptables}" -F

        "${iptables}" -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
        "${iptables}" -A INPUT -i lo -j ACCEPT

        for IP in "${bannedIPs[@]}"
        do
                "${iptables}" -A INPUT -s $IP -j DROP
        done

        for i in "${tcpPorts[@]}"
        do
                "${iptables}" -A INPUT -p tcp --dport $i -j ACCEPT
        done

        for k in "${udpPorts[@]}"
        do
                "${iptables}" -A INPUT -p udp --dport $k -j ACCEPT
        done

        "${iptables}" -P INPUT DROP
        "${iptables}" -P FORWARD DROP
        "${iptables}" -P OUTPUT ACCEPT
done

# Configure ICMP rules separately for v4 and v6
iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
if [ "${IPv6_Enabled}" == "True" ]
then
        ip6tables -A INPUT -p ipv6-icmp -j ACCEPT
fi

if [ "${SSH_on_IPv4}" == "True" ]
then
        # Configure port 22 (ssh) separately as Fail2Ban does not support IPv6
        iptables -A INPUT -p tcp --dport 22 -j ACCEPT

        if [ "${Fail2Ban_Enabled}" == "True" ]
        then
                # Restart Fail2Ban
                service fail2ban start
        fi
fi

# Show result
sleep 1
for iptables in "${tables[@]}"
do
        "${iptables}" -L -v
done