Firewall

Different ways to handle iptables.

Using iptables-persistent on Debian

Note: In use on vrijdagmiddagborrel.

It's basically a set of iptables plugins for netfilter-persistent, which itself is a loader for different netfilter configuration. Once installed, it will take care of restoring rules at boot time, and through a small helper, can be used to reload/update/save rules on the fly.

Installation and config

• Installation:

apt install iptables-persistent netfilter-persistent

• Add/change iptables rules located at /etc/iptables/rules.v4 and /etc/iptables/rules.v6

Usage

• Apply new rules after changes made to rules.v* files and check result

netfilter-persistent reload
iptables -L

iptables oneliners

• list all rules from all chains

iptables -L

• block an IP

iptables -I INPUT -s 192.168.111.111 -j DROP
iptables -I OUTPUT -d 192.168.111.111 -j DROP