Make it executable: chmod +x /etc/network/if-pre-up.

sbin/iptables-restore < /etc/iptables.up.conf Next, flush out all your existing iptables rules by running the command below. The command below copies the rules.v4 and rules.v6 files to your home directory.

To start iptables on boot, create this file: nano /etc/network/if-pre-up.d/iptables First, make a backup copy of your existing iptables rules. Happy? Save it for real (this and the previous file names are arbitrary, you can pick a different path): iptables-save > /etc/iptables.up.confįor the firewall to be useful, it should always run on boot. Use iptables -L -n to get a 'normal' view without translated port numbers. Note how known ports such as 80 are shown as http, 443 as https, etc. Save the rules to a test file: sudo iptables-save > /etc/ When done adding rules, check the list in iptables: sudo iptables -L Optionally, allow ping: sudo iptables -A INPUT -p icmp -m icmp -icmp-type 8 -j ACCEPTīlock inbound traffic that is not allowed by any of your rules: sudo iptables -P INPUT DROP Sudo iptables -A INPUT -p tcp -dport 22 -m state -state NEW -j ACCEPTĪdd a line for each port you wish to open, change the port number or tcp/udp where needed. sudo iptables -A INPUT -p tcp -dport 80 -m state -state NEW -j ACCEPT 80 for http, for example, or SSH (default 22). sudo iptables -A INPUT -s 69.63.176. Open a port that you want to be accessible from the outside. Like this:Īllow connections that are, well, ok: sudo iptables -A INPUT -j ACCEPT -m state -state ESTABLISHED,RELATED Install it the regular way: sudo apt-get install iptables