AWS Firewalls 101: Stateful vs. Stateless

AWS Firewalls 101: Stateful vs. Stateless

Hey there, fellow cloud enthusiast! Today, let's dive into the basics of stateful and stateless firewalls in AWS.
Firewalls are the unsung heroes of network security, keeping the bad stuff out while letting the good stuff in.
But did you know there are different types? Let's break it down.

Stateful Firewalls
Think of stateful firewalls as the smart gatekeepers of your network. They remember past interactions. If you let someone in, they remember and let them out too without you having to tell them again. This is super handy because you set fewer rules, and it keeps things simple.

Why They're Awesome:

Connection Savvy - They track ongoing connections, making life easier by allowing return traffic automatically.
Less Work - Fewer rules to manage means less hassle.

In AWS, Security Groups are your go-to stateful firewalls. It allows incoming traffic on port 80 for your web server, and the return traffic flows back out without additional configuration.

Stateless Firewalls
On the flip side, stateless firewalls are like diligent security guards checking every single packet without any memory of the past. They need explicit instructions for everything, both coming in and going out.

Why They're Cool:

Super Fast - They can handle lots of traffic quickly because they don't track connections.
Detailed Control - You get to set detailed rules for everything, giving you granular control.

AWS Network ACLs (Access Control Lists) are your typical stateless firewalls. You'll need to write specific rules for both inbound and outbound traffic, which gives you precise control but requires more setup.

In a nutshell, most AWS setups use a combination of both. Security Groups manage traffic to your instances, while Network ACLs add an extra layer of subnet-level control.

Let's have a quick demo on the next blog post about the concept of stateful and stateless firewalls.