What is NAT Firewall and Why It’s Important

Published by Joel Timothy on March 25, 2019

When you connect to the internet, there are lots of packets being sent and received, and all these are governed by various rules and protocols. At the same time, other processes work together to check errors, speed up the process, organize packets etc.

To secure all these processes, one of the protocols employed is the NAT Firewall, and it’s used by various VPN services.

A VPN and NAT firewall

Both a VPN and a NAT Firewall are tools that are important for protecting users while on the internet. The two are however commonly used together by various VPN services.

Other providers see the NAT firewall as an unnecessary tool since the same loophole that it addresses can be addressed by a router/ server using shared IP addresses.

VPN Defined

A VPN works by encrypting your device’ traffic and then securely tunneling it to a remote server.

Through this encryption, no third-party, not even your ISP, can see your traffic or even intercept your connection. This therefore protects you from hackers and other malicious internet users.

NAT Firewall Defined

A regular firewall acts like a barrier between a trusted network and an “outside” network, especially the internet.

This firewall can be implemented using software or hardware, and its work is to prevent any unwanted communications, which is good for security.

NAT stands for Network Address Translation, and it makes sure that the devices connected to a network have a single IP address. After that, it ensures that when a connected device makes a certain request, that’s the only information that is returned. This means that it compares all incoming connections, and every packet that is not recognized gets destroyed by this “wall of fire.”

Note: NAT Firewall can only be used with networks that use dedicated IP addresses- not idea for privacy and anonymity.

Why a NAT Firewall is especially important while on mobile

Unlike desktop operating systems that come with inbuilt firewall protection, mobile operating systems don’t.

Browsing the internet without a firewall therefore leaves you exposed to hackers and bots that look for loop holes in your operating system. Since you have no protection against these requests, malicious traffic can reach your mobile device and may execute various exploits.

This is even aggravated by the fact that we regularly use our mobile phones to connect to public Wi-Fi hotspots, which are generally unencrypted.

Why doesn’t  ExpressVPN  use a NAT Firewall

Not all VPNs use a NAT Firewall, as some don’t see the need to. One of such VPNs is ExpressVPN, which is one of the most respected leaders in the market.

Since NAT Firewall requires every user to have a single IP address, it can’t be used everywhere.

According to ExpressVPN, a NAT Firewall is used to prevent a vulnerability that is brought about by the use of dedicated IP addresses, something that the VPN doesn’t do.

This is because dedicated IP addresses reduce your privacy and anonymity, as your IP address and activities can be easily linked to you.

In a network that uses shared IP addresses, the server acts as a firewall by default, and so a NAT Firewall is not important. The Firewall is therefore only needed because assigning of unique IP addresses to each user can easily leave various ports open, presenting a chance for attack. The VPNs that offer unique IP addresses then use NAT Firewall to close these ports, but others sell it as an extra security feature.

Do I need a NAT Firewall alongside my VPN?

If your VPN offers dedicated IP addresses, then you definitely need a NAT Firewall. However, most of these VPNs usually have the NAT firewall bundled within the service such that you don’t have to pay extra for it.

The best of such VPNs are:

1NordVPN (Check out our detailed NordVPN review)

2IPVanish (Check out our detailed IPVanish review)

However, a VPN that completely doesn’t offer dedicated IP addresses like ExpressVPN doesn’t necessarily need a NAT Firewall. The VPN uses AES 256-bit encryption, and their servers remember all requests’ sources and the destinations. They then broadcast these requests while keeping the ports closed, just like a firewall would.

Joel Timothy
Joel is an online privacy advocate, writer, and editor with a special interest in cyber security and internet freedom. He likes helping readers tackle tricky tech and internet issues, as well as maximize the boundless power of the internet.