S etting Up a Firewall with iptables

A firewall is basically a security tool that controls what kind of traffic can go in and out of a network. You can think of it like a gatekeeper: it blocks unwanted connections and lets the safe ones through.

Firewalls are useful for stopping outside attacks, but keep in mind — they can’t protect against everything. For example, they won’t help if the attacker is already inside your network, or if the app you’re using has serious bugs.

Here are some common things firewalls usually do:

• Analyze and filter packets.
• Block certain types of content or protocols.
• Handle authentication and encryption for connections.

In this guide, we’ll use iptables to set up a firewall on a PC that acts as a router.

For the full step-by-step instructions, check out the PDF here.