Databases, Systems & Networks

Saving iptables rules for reboot

On a server, iptables rules don’t reload automatically at reboot. You need to reload the rules using ax executable shell scripture a dedicated utility that will load them at the same time as the program itself, i.e. with the kernel.

Depending of the version of Linux you use, you can select different methods:

sudo su
iptables-save > /etc/iptables.rules

In /etc/network/if-pre-up.d/iptables, put:

#!/bin/sh
iptables-restore < /etc/iptables.rules
exit 0

After, in /etc/network/if-post-down.d/iptables, put:

#!/bin/sh
iptables-save -c > /etc/iptables.rules
if [ -f /etc/iptables.rules ];
       then iptables-restore < /etc/iptables.rules
fi
exit 0

After, give permission to the scripts:

sudo chmod +x /etc/network/if-post-down.d/iptables sudo chmod +x /etc/network/if-pre-up.d/iptables

Another scenario is to is to install iptables-persistent:

sudo apt-get install iptables-persistent

After it’s installed, you can save/reload iptables rules anytime:

    sudo /etc/init.d/iptables-persistent save 
    sudo /etc/init.d/iptables-persistent reload

Or if you use Ubuntu server 16.04, things are simpler:

    sudo netfilter-persistent save
    sudo netfilter-persistent reload