Setup linux firewall (debian)

README.md

file location :

• /usr/local/src/firewall.sh

chown root /usr/local/src/firewall.sh
chgrp root /usr/local/src/firewall.sh

ln -sf /usr/local/src/firewall.sh /usr/local/sbin/firewall

use iptable-persistent to save firewall rules.

apt-get install -y iptable-persitent

firewall.sh

#!/bin/sh

interface_0=eth0
interface_1=eth1

public_ip="192.168.2.2"

stop() {
        #reset policy
        iptables -t raw -P PREROUTING ACCEPT
        iptables -t raw -P OUTPUT ACCEPT

        iptables -t mangle -P PREROUTING ACCEPT
        iptables -t mangle -P INPUT ACCEPT
        iptables -t mangle -P FORWARD ACCEPT
        iptables -t mangle -P OUTPUT ACCEPT
        iptables -t mangle -P POSTROUTING ACCEPT

        iptables -t nat -P PREROUTING ACCEPT
        iptables -t nat -P INPUT ACCEPT
        iptables -t nat -P OUTPUT ACCEPT
        iptables -t nat -P POSTROUTING ACCEPT

        iptables -t filter -P INPUT ACCEPT
        iptables -t filter -P FORWARD ACCEPT
        iptables -t filter -P OUTPUT ACCEPT

        #Empty table
        iptables -t raw -F
        iptables -t mangle -F
        iptables -t nat -F
        iptables -t filter -F

        # Remove chain
        iptables -t raw -X
        iptables -t mangle -X
        iptables -t nat -X
        iptables -t filter -X
}

start() {
        # set firewall rule hear
}

show() {
        echo "RAW tables"
        iptables -S -t raw
        echo ""
        echo "Mangle table:"
        iptables -S -t mangle
        echo ""
        echo "Nat table: "
        iptables -S -t nat
        echo ""
        echo "Filter table: "
        iptables -S
        echo ""
}

case "$1" in
        start)
                start
                ;;
        stop)
                stop
                ;;
        restart)
                stop
                start
                ;;
        show)
                show
                ;;
        *)
                echo "Usage: $0 {start|stop|restart|show}"
                exit 1
                ;;
esac
exit 0

gistfile1.txt

# Make sur /usr/local/sbin path is in en $PATH env var
# Display current firewall
firewall show

# Start firewall
firewall start

# Stop firewall
firewall stop

# Restart firewall
firewall restart

# Set current firewall as persistent
iptables-save

# Display the current persistent table
cat /etc/iptables/etc/iptables/rules.v4