In the medieval world, lords relied on castle walls to keep them save from marauding armies. When nation states emerged, borders and armies took over. And int he age of the Internet, firewalls have taken over as our primary line of defense. Without firewalls, we would be at the mercy of hackers, spies, thieves – a whole host of people who don’t have our best interests at heart. So it definitely helps to learn a bit more about these essential digital barriers.

NAT firewalls are one of the most common forms around, and they are specifically relevant to Virtual Private Network (VPN) users. We’ve looked at NAT in more detail elsewhere, so feel free to brush up on your knowledge if you’re new to the concept. And when you’re up to speed, let’s find out more about what NAT firewall is, and why it matters to your security setup.

What is a NAT firewall and how does it work?

In the term NAT firewall, the NAT stands for Network Address Translation. NAT is basically a technical method which is used to make the use of IP addresses much more efficient, which really matters in a world where usable IPv4 addresses are rapidly running out.

With an NAT router in place (which the vast majority of homes and offices have), it’s possible to connect multiple devices to the wider internet using a single IP address. It’s why you can read this on our website, while your brother is playing Call of Duty online, and your sister is checking her Facebook on her phone – all in the same house, using the same web connection.

How does NAT relate to firewalls? Well, it’s all down to VPNs. Normally, NAT routers screen out undesirable IPs and effectively filter out a lot of malicious traffic. But when you use an NAT firewall VPNservices can disrupt it. VPNs create “tunnels” which effectively bore straight through NAT protections, potentially leaving your computer vulnerable to all kinds of attacks.

So, in answer to the question what is a NAT firewall and how does it work, the first part is simple: It’s a way to protect yourself when using VPNs. Let’s unpack that in a bit more depth to help you understand why that matters.

How VPNs use NAT firewalls to protect their users


Without a VPN installed, your internet connection would look something like this: Local computer – NAT firewall – ISP – Wider internet (and vice versa). As you can see, the NAT router/firewall acts as a filter. When you send data, it accommodates multiple devices. When you receive data, it knows which device to route it towards, and what you requested.

When a VPN is installed, the diagram might look more like this: Local computer – VPN – ISP – Wider internet. Here, the NAT router has been totally displaced, and your IP address is being anonymized by the VPN. In this case, many VPNs choose to add a specialist NAT firewall router in between the VPN – ISP connection. That way, you can enjoy the protections afforded by standard NAT routers and the privacy of a VPN.

This can have numerous security advantages for VPN users. For instance:

    • Hackers will find it much tougher to investigate your connection to find open ports or inject malware into your data transmissions.
    • Every packet of data sent over your VPN will now be inspected and verified, so you’ll know where it is coming from, and whether you are sending the correct data.
    • NAT firewalls also provide some protection against encryption attacks, helping to maintain the integrity of the VPNs privacy services.

One way of visualizing the role of NAT firewalls is to think of your computer as a home. Normally, you would have access control via a doorbell or keypad. But your home is also easily identified via an address and house number. When you leave the house or receive mail, anyone can see.

Suppose you wanted a private way to leave the house without being spotted. In that case, you could build a tunnel to a location a mile away, and just emerge from the other end without anyone noticing. But tunnels work both ways, providing an unregulated entrance to your original home. An NAT firewall simply installs a way of regulating access on your handy new tunnel, allowing you to safely anonymize your life.

Do VPNs and NAT firewalls have to go together?


When you research the world of VPNs, you’ll find that not all providers offer NAT firewalls are routine. In fact, these protective barriers are still seen by many people as an optional extra in a VPN’s security arsenal. Why is this, and are these services correct?

For example, ExpressVPN are one of the world’s leading VPN providers, but they have a policy of not prioritizing NAT firewall router protection. For them, these firewalls are totally unnecessary.

In their opinion, NAT firewalls only become necessary when VPNs work by assigning their users specific IP addresses. But not all VPNs do this. Instead, if they operate like ExpressVPN, they share IP addresses between their users – which they state has major privacy advantages.

It also negates some of the hazards associated with losing NAT protection when you fire up VPN tunnels. As they explain, VPNs which use individual IPs can end up leaving ports open, and these ports are a key vulnerability.

In ExpressVPN’s words, open ports could allow “a passive observer, such as the ISP of the VPN service, could observe unencrypted traffic to deanonymize a user.” But if the VPN doesn’t do this, there’s less need for extra firewall protection.

So it’s important to understand that there’s a debate within the VPN community about the NAT firewall VPNrelationship. It’s not quite as simple as saying that every VPN user must invest in extra NAT protection. After all, some of the most respected VPNs in the world explicitly reject NAT firewalls, seeing them as a waste of resources and a potential security risk.

What about the advantages of NAT firewalls and VPNs?

Having reported the dissent from ExpressVPN, it remains true that many leading VPNs offer the option of installing an NAT firewall alongside their security and privacy tools. Do you need to take them at their word and pay extra for this feature?

Firstly, it’s important to note that not all NAT firewall add-ons are expensive. In fact, it’s common for a VPN to offer a free NAT firewall with their client and subscriptions. So you don’t really need to pay extra for the service.

Secondly, it makes more sense to have an additional firewall installed if you manage multiple devices on the same VPN connection. For instance, businesses often choose to back up their antivirus and antimalware systems with NAT firewalls. This isn’t just to protect against external threats, but to ensure that all devices within their LAN network are properly separated and interface efficiently with the wider internet.

And remember what ExpressVPN said: NAT isn’t an issue for VPNs which assign multiple users to the same IP address. But most VPNs aren’t like that. They tend to give you a unique IP address. In those situations, it is definitely advisable to have extra NAT protection. In fact, those VPNs would be virtually useless without NAT firewalls in place.

So, given all of that, what are the best NAT firewall VPN providers?

Choose the right VPN to ensure NAT firewall protection

best vpn providers

As you’ll know if you’ve waded through long lists of VPN companies, the features they offer vary wildly, along with their prices and reputation. Because poor NAT protection can pose a huge security risk, it’s vital to pick a VPN which takes the risks seriously. Thankfully, there are plenty of leading contenders who do just that.

1. IPVanish – Known for their speed and focus on privacy, IPVanish have long understood the need for proper NAT safeguards. However, they don’t include local NAT firewalls. Instead they use a firewall between their servers and ISPs, allowing them to let users share the same IP address – a little like ExpressVPN’s system, just with extra NAT protection.

2. CyberGhost – Probably the best VPN for torrenting, CyberGhost make NAt protection a standard part of their package, along with 256 bit AES encryption, IPv6 leak protection and IP sharing – so pretty much every security concern is well covered.

3. NordVPN – One of the most respected VPNs around, NordVPN assign every user their own IP address, which makes NAT filtering absolutely essential. And that’s exactly what you get, along with plenty of other security countermeasures. As the company explains, NAT filtering effectively screens material that you didn’t “request”, but that doesn’t necessarily catch malware and viruses, so they’ve bundled in high-level anti malware tools as well.

4. PureVPN – Another widely used VPN across the world, PureVPN refer to the NAT issue as “port forwarding”, which is essentially the same thing as NAT firewall protection. Their VPN includes the option to switch on port forwarding for as many as 5 devices. But it’s not automatically enabled, so bear that in mind if you’re a PureVPN fan.

5. Ivacy – Another popular, solid VPN, Ivacy have taken the option of offering NAT as a paid-for extra. Their plans tend to be fairly affordable, and NAT is often $1 per month extra, so it’s not a huge outlay. Their NAT service is also tailored to business users in a way that many other VPNs aren’t, offering readdressing, port forwarding, port multiplexing, and multiple device protection. Definitely worth checking out.

All of the VPNs listed above prioritize NAT as a security issue, so you can be confident that they will effectively regulate inbound and outbound traffic entering your systems. Not all of them free NAT firewalladd-ons, and it’s often hard to tell exactly how “free” other packages are, given that the total package cost varies so much.

In any case, these are elite VPNs which tend to deliver what you pay for – solid privacy protection.

Keep your borders secure with NAT firewall VPN protection

VPNs can solve a lot of privacy and security issues. They can erect a barrier against snoopers, prevent hackers hijacking our email accounts, leap over geoblockers, and much else besides. But these advanced security tools create their own problems – and dealing with NAT is probably the most important.

As we’ve seen, VPNs approach NAT differently. Some find workarounds which make it less of an issue. Others offer specialist firewalls which can make VPN tunnels secure. As ever, pick a service which matches up price and quality, and you’ll be able to browse the web without worrying about the origins of data packets flowing across your network.