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What is a NAT firewall and what does it do?

May 23, 2018 · 3 min read

What is a NAT firewall and what does it do?

Browsing the internet seems simple – you click on what you want and you get it. However, there are various tools working in secret to make your experience as secure and convenient as possible.

One of those tools is the NAT firewall. But what is NAT? What does it do, and why is it important that NordVPN uses it?

What is a firewall?

If your computer is a busy CEO, then a firewall is the CEO’s secretary, sorting the mail and making sure that only mail that the CEO actually wants gets through. When you browse the internet, you send requests for information – when loading a website, clicking on a link, or opening your email account. The firewall compares the information that’s returning with the information you requested – everything that’s a match gets through, and everything that it can’t recognize is immolated in a vicious wall of fire (or so the term “firewall” would have you believe)!

What does NAT stand for?

NAT stands for Network Address Translation. NAT gives all of the devices connected to a router a single IP address. Then, when those devices connect to the internet, it makes sure that each of those devices gets the packet it asked for. If a firewall is a secretary, a NAT firewall is a secretary that sorts mail for multiple recipients at a single office address. When your laptop, smartphone, and desktop are all on one router, your firewall makes sure Facebook doesn’t open on your desktop when you check it on your phone.

By design, NAT is not a security tool, but it certainly helps improve your security anyway. First of all, it hides the IP addresses of any devices on your network from the outside world, giving them all a single address. Secondly, it requires every incoming packet of information to have been asked for by a device. If a malicious data packet isn’t on the list of expected communications, it is unceremoniously rejected. This secretary doesn’t like junkmail! Some firewalls can even use whitelisting to block unauthorized outgoing traffic, so if you do manage to contract a piece of malware or a bot, your firewall may prevent it from communicating with its owner.

More sophisticated attacks can make it through, especially ones that employ phishing or social engineering methods, but the NAT firewall is still an important first line of defense. Without one, it would be simple for any amateur hacker to access your computer simply by learning your IP address. Thanks to its tireless work, you can be shielded from tons of threats every day that you’ll never even see. However, a NAT firewall is not enough. If you want to ensure the best online security possible, you should add NordVPN to the mix.

Why a NAT firewall is not enough

A firewall is a relatively simple tool that isn’t capable of ensuring the best online security possible. Remember, it only blocks traffic that you don’t request. If you’ve asked to open or download a malicious file or piece of software, your firewall will not stop you. NordVPN, on the other hand, has a feature called CyberSec. When you switch on CyberSec, it will prevent you from visiting any of the sites stored on its extensive blacklist of malicious websites.

For maximum security and privacy, use NordVPN along with antivirus software and a NAT firewall. If your OS offers its own built-in firewall, we recommend switching it on. These firewalls are usually even more sophisticated than basic NAT firewalls and can do more to protect you.

Last but not least, read about other safe browsing practices we’ve featured on our blog. After all, even the most secure castle in the world can fall if hackers can trick the person inside into opening the gate!

How to use the internet safely:


Daniel Markuson
Daniel Markuson successVerified author

Daniel is a digital privacy enthusiast and an Internet security expert. As the blog editor at NordVPN, Daniel loves to serve up generous helpings of news, stories, and tips to help people stay private and secure.


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