In today's world, just about everything we do involves the internet, whether it's working, shopping, or just catching up with friends online. But with all that activity comes risk. That's where firewalls come in.
So, what is a firewall and how does it work? In simple terms, it’s a bit like having a security guard for your computer or network. Let’s take a closer look at how firewalls work and how you can use them to stay protected.
What Is a Firewall?
A firewall is a type of digital security barrier. It can be a physical device, a piece of software, or a mix of both. Its main job is to sit between your network (like your Wi-Fi at home or your office system) and the rest of the internet.
Think of it like a bouncer at a nightclub. It checks who’s trying to get in, and only lets the right people through. If someone turns up on the “not welcome” list, they’re turned away straight away.
Firewalls work based on a set of rules. If a bit of data meets the rules, it gets in. If not, it’s blocked. Some of the clever techniques firewalls use include:
- Packet filtering - quickly checks data packets for anything unusual
- Proxy services – acts as a go-between for your devices and the internet
- Stateful inspection – keeps track of ongoing connections to spot anything out of place
How Does a Firewall Work Day-to-Day?
Imagine your firewall as a digital doorman. It looks at every little packet of data (like the digital version of an envelope) coming in or going out of your network. It checks who it’s from, where it’s going, and what’s inside.
If everything looks okay, the data is allowed through. If not, the firewall quietly blocks it or raises a red flag.
It does this by checking things like:
- IP addresses (where the data came from or is heading to)
- Port numbers (which digital ‘door’ is being used)
- Protocols (the way data is being sent)
To help it make these decisions, the firewall uses:
- Basic filtering
- Acting as a middleman (proxy)
- Tracking the flow of connections over time
All of this happens in the background while you go about your day, helping stop hackers, viruses, and other cyber nasties from sneaking in.
How Firewalls Block Unwanted Traffic?
Here's how a firewall keeps things in check, step by step:
1. Keeps an Eye on Traffic
It watches every bit of data going in and out of your network.
2. Applies the Rules
It checks each packet against a set of rules to decide if it's allowed or not.
3. Looks Inside
It inspects where data is coming from, where it's headed, and what it contains.
4. Makes a Decision
The firewall then chooses to let the data in, block it, or send an alert if something seems fishy.
5. Logs Everything
It keeps a record of what it's blocked or allowed, which helps with spotting suspicious patterns later.
How Does a Firewall Protect Data?
Firewalls do more than just block dodgy websites—they actively protect your data from a range of online threats. Here are some of the common risks firewalls can help defend against:
1. Backdoors
These are hidden “doors” in your system that hackers use to sneak in—often through software bugs or poorly secured apps. Firewalls can spot when these doorways are being targeted and shut them down before anything nasty gets in.
2. Denial-of-Service (DoS) Attacks
This is when hackers flood a server with requests until it gets overwhelmed and stops working. Some firewalls are smart enough to tell if a request is real or fake—and block fake ones to keep your network running smoothly.
3. Macros
Macros are small scripts used to automate tasks in programs like Microsoft Word or Excel. Hackers can sneak harmful macros into seemingly normal files. A firewall can inspect these files and block anything suspicious before it reaches your device.
4. Remote Logins
Allowing someone to access your computer remotely can be helpful, but also risky if the wrong person gets in. Firewalls can control and monitor remote access to ensure only authorised users are let through.
5. Spam
Spam emails aren’t just annoying, they can also contain harmful links or attachments. Firewalls can scan incoming emails and block the dodgy ones before you even open them.
6. Viruses
Viruses spread quickly and can cause anything from annoying glitches to total data loss. While a firewall can detect some viruses by checking data packets, it's best to use it alongside antivirus software for full protection.
What Does a Firewall Actually Do for You?
A firewall's main job is to limit who and what can access your private network. Instead of every device being open to the internet, everything has to go through the firewall first.Because of this, it can:
- Block anything it doesn’t recognise or trust
- Stop unwanted software or people from getting in
- Keep track of all connection attempts, giving you a helpful record if something goes wrong
What Can Firewalls Help Protect Against?
Firewalls can be adjusted to meet your exact needs. They’re useful for loads of different situations, including:
- Stopping Hackers and Malware: They can block access from known dodgy sources before they do any damage.
- Parental Controls at Home: You can use a firewall to block certain websites or content to keep things family-friendly.
- Workplace Internet Rules: Businesses often use firewalls to stop staff from accessing social media or streaming sites during work hours.
- Country-Level Restrictions: Some governments use firewalls to control what websites can be accessed within their borders.
How to Make the Most of Firewall Protection?
Having a firewall is a great start—but it’s only effective if it’s set up and looked after properly. Here are some handy tips:
1. Keep It Updated
Firewalls need regular updates to protect against new threats.
- Home users can usually update straight away.
- Businesses should check everything's compatible before updating, but shouldn't delay for too long.
2. Use Antivirus as Well
Firewalls help filter traffic, but they don't catch every virus. Use a good antivirus tool alongside your firewall for full protection.
3. Be Strict About Access
- Block everything by default and only allow trusted sources.
- Only open the ports you actually need.
- Limit user access so that if something does go wrong, the damage is limited.
4. Split Your Network Up
Dividing your network into smaller parts helps stop threats from spreading.
- You can even use firewalls internally to control movement between different areas.
5. Have a Backup Plan
Always backup important data and have systems in place to keep things running if something goes wrong.
Conclusion
Now that you know what is a firewall and how does it works, you can see just how important it is for keeping your digital life secure. From blocking dodgy data to spotting suspicious activity, firewalls are one of the best tools out there for staying safe online.
Looking to set up strong firewall protection but not sure where to start? Talk to the experts at Radium and get customised cybersecurity solutions that fit your needs.