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What is a NAT Firewall? How Does It Work and Do You Need One?

If you’re unsure about what exactly a NAT firewall is or what it does, stay on this page. Today’s guide teaches you everything you need to know about this essential cybersecurity technology, plus how to make it play nice with your VPN for the ultimate protection.

There are countless protocols that sit between you and the internet. Some are designed to carry data back and forth, while others speed the process up, perform error checking routines, and reassemble packets of information so they display as a unified whole.

Then there’s the technology designed to keep us safe; NAT firewalls fall into this category. They’re one of the early lines of defense against malicious attacks on our internet connected devices, and they do their job without us even knowing it. Today’s primer walks you through everything you need to know about this technology, plus shares a few tips on how to further boost your security with a VPN.

NAT Firewalls, the basics

The internet runs on packets of data. Countless numbers of these packets are sent back and forth each time you make a request, whether that be a simple website loading in your browser or a movie streaming to your TV. Packets need to be sent to precise locations, and to accomplish this, each one is stamped with an IP address. Each device that connects to the internet is assigned a unique IP, which acts a lot like a mailing address. This lets ISPs know who gets which piece of data so you actually receive the information you request.

To help handle the load of devices connecting from a single home, routers do much of the data packet sorting. Your internet service provider assigns you a single IP address when you connect. Your router then creates internal IPs for each device that connects through it. Turn on your phone’s Wi-Fi and it gets an internal IP. Switch on an e-reader, gaming console, tablet, etc. and they, too, get internal IPs. In short, when packets of data come to your router, it sorts them to the devices that are requesting the information.

This is where firewalls come into play. Just about everyone who’s used a computer knows that firewalls are tools that block unwanted data. This prevents malicious bots and hackers from sneaking into your computer through unauthorized connections. Only the traffic you specifically requested is allowed through, everything else is simply discarded or ignored.

NAT stands for Network Address Translation, which is a fancy way of saying “sorting.” Routers use NAT to modify the IP address information stamped on data packets so it knows which of your connected devices to send which packets of data to. A byproduct of this sorting process is filtering out unrecognized packets and discarding them, which is why it functions like a firewall. NAT ensures everything gets to where it needs to go and nothing extra is thrown into the mix.

Why do VPNs advertise NAT firewall features?

If your router has a NAT firewall, why then do VPN services act like it’s such a special feature? The answer has to do with the way VPNs operate. When you run VPN software on your computer, it encrypts every packet of data that leaves your device. Encrypted data is unreadable to any person and any piece of hardware that doesn’t have the right cipher key, including your own devices.

Only two parties can unlock this encryption: your VPN software, and the VPN servers. Your router’s NAT firewall can’t read encrypted packet headers, so it simply passes data back and forth without knowing the IP address attached to it. This means that even malicious data will slip through local NAT firewalls, as the router is essentially blind.

A VPN with NAT firewall features takes care of the sorting for you. Since the VPN sits between you and the internet, the service deploys a NAT firewall on the outside of its servers. For example, you send encrypted data through your router and to the VPN’s network. The VPN decrypts it and handles the request (fetching a website or downloading a file). The VPN’s NAT firewall filters out any unusual activity coming from the internet, then the correct information is encrypted and sent back to your computer. It performs essentially the same function as your router’s NAT firewall, only since the local version can’t do its job with encrypted data in place, the VPN takes care of that for you.

Do you have to have a NAT Firewall?

Strictly speaking, the internet will still operate without a local or a VPN version of a NAT firewall in place. It’s not a good idea to go without one, however. NAT firewalls are a first line of defense against malicious attacks; they stop hackers before they even reach your device, which is the only way to ensure none of your data is taken.

NAT firewalls are even more useful when mobile devices and other non-PC hardware are involved. Nobody runs firewall software on their smartphone or gaming console, so what’s to stop a hacker from walking right in? NAT firewalls protect these devices without having to install extra software.

You may be thinking “I’ve never been attacked before; I think I’ll be safe without a NAT firewall.” The only reason you think you’ve never been targeted by a hacker or a data bot is because the NAT firewall unceremoniously stopped it in its tracks.

Using firewall software with NAT firewalls

NAT firewalls aren’t perfect, and neither is the firewall software you can download and install. However, using both in tandem is an excellent method of filtering out as many unwanted connections as possible. Hackers are constantly looking for new ways to exploit bugs in the HTTP process or operating systems. It’s always better to have multiple overlapping forms of protection in place to ensure you stay safe.

How to choose the right VPN

Now that you know how useful NAT firewalls can be, you’ll want to search for the best VPNs that offer high security along with NAT services. It can be difficult to weigh all of the privacy and encryption options against speed and server distribution numbers, especially if this is the first time you’ve looked for a VPN. We used the criteria below to build a recommended list of VPNs with NAT firewalls. Use them to refine your own research so you can make an educated and cost-conscious selection.

  • NAT firewall support – Most of the top-tier VPNs offer NAT firewalls as part of their service. Others provide similar workarounds to deliver the same level of protection.
  • Encryption strength – The foundation of a VPN’s security rests upon its encryption strength. Most good-quality providers deliver 128-bit or 256-bit AES encryption to all of their servers, which is ideal for online activities. 
  • Logging policy – All of your traffic passes through a VPN’s servers. If they keep detailed logs of your browsing history, that data could end up in government or third-party hands. Make sure your VPN has a strict zero-logging policy that covers as many areas as possible, especially traffic and DNS requests.
  • Software – To use a VPN, you need to be able to install it on all of your devices. This means having custom software for smartphones, tablets, laptops, and even Chromebooks. Make sure your most commonly used devices are covered by the VPN’s apps before signing up.
  • Speed Encryption adds data to each packet of information, which results in a slower download speed. Good VPNs can work around this limitation without sacrificing privacy by offering fast servers and customized software solutions.

Top-rated VPNs with NAT firewalls (or similar functionality)

With the above criteria in mind, we’ve gone to the trouble of narrowing down the crowded VPN market so you can make the best decision for your needs. We’ve rated each for its security, speed, usability, and of course, NAT firewall functionality:

1. ExpressVPN

ExpressVPN - Editors choice

ExpressVPN is one of the easiest-to-use VPNs, and it offers incredible speeds to users around the world. It starts with a wide network of 3,000+ servers in 94 different countries, enough to ensure you can find a close connection for top speeds and lag-free gaming. You’ll have unlimited bandwidth to enjoy these download speeds as well, along with endless access to P2P networks and torrents, strong 256-bit AES encryption, DNS leak protection, and reliable uptime for the entire network.

ExpressVPN doesn’t specifically offer a NAT firewall, but there’s a good reason for that. ExpressVPN’s servers have built-in NAT firewall features that reject unrequested packets of data, which keeps out malicious third parties by default.

Read our full ExpressVPN review.

  • Unblocks US Netflix
  • Superfast servers (minimal speed loss)
  • AES-256 encryption
  • No logging policy well enforced
  • Live chat support available.
  • Power-users configuration options.
BEST OVERALL VPN: ExpressVPN offers the best balance of privacy, performance, and price. Super fast servers. No logs. 30-day money back guarantee. Get 49% OFF on the yearly plan.

2. IPVanish


If you want to stay safe when you go online, you need to be invisible. IPVanish provides a ton of features that help keep you private and secure when you browse the internet, and it does it all with extremely fast servers with very little lag. If you need anonymous and unrestricted access to torrents or P2P networks, IPVanish will deliver. If you need to bypass censorship blocks or keep your location hidden while you travel, IPVanish will deliver that, too. To top it all off, the IPVanish network has over 40,000 IP addresses spread across 1,300 servers across 60 different countries, a highly robust offering by any standard that spoils you for choice in optimizing your connection.

IPVanish states up front that it deploys NAT firewalls to help keep malicious connections and data packets at bay. This holds true for every server in its worldwide network.

IPVanish also comes with the following features:

  • Lightweight and easy-to-use VPN apps for PC, laptops, smartphones, tablets, and even Chromebooks.
  • Unlimited bandwidth, no speed caps, and no restrictions on P2P or torrent traffic.
  • Secure, fast, and anonymous downloads ideal for torrent and Kodi users.
  • A strict zero-logging policy on all user traffic.

Read our full IPVanish review.

GREAT VALUE: Sign up for a full year of IPVanish, just $4.87 per month, and get a 60% discount. If you’re not completely satisfied, each plan is covered by an amazing 7-day money-back guarantee.

3. PureVPN


PureVPN is a fast, friendly, and privacy-aware VPN service designed to make the internet a safer place for everyone. It starts with strong 256-bit encryption to keep prying eyes away from your data. This is backed by a zero-logging policy that covers all traffic, kill switch and DNS leak protection features, as well as a massive network of over 2,000 servers in 141 countries. PureVPN owns and operates this entire network themselves, which allows them to customize hardware and software as they please and steer clear of third parties for increased data security.

PureVPN offers NAT firewalls as a paid add-on to its regular service. Once you sign up for the VPN, you can access and enable the NAT firewall in the member’s area for a low monthly fee.

PureVPN’s features at a glance:

  • Excellent custom apps for all modern operating systems, smartphones, tablets, PCs, and more.
  • Advanced features include anti-virus protection, ad-blocking, and anti-phishing measures.
  • Self-owned network of servers for enhanced privacy and security.

Read our full PureVPN review.

READER SPECIAL: Save a massive 74% here on the 2-year plan, just $2.88/mo with a 31-day money back guarantee.

4. VyprVPN


VyprVPN delivers some of the most unique and most useful privacy features in the VPN marketplace. For starters, the company owns and operates its entire network of servers, over 700 in 70 different countries. This gives them the freedom to upgrade and customize each server to meet their own specifications, and it keeps third parties out of the picture entirely. VyprVPN also offers its exclusive Chameleon technology for increased anonymity and security. Chameleon scrambles the metadata in encrypted packets to help defeat deep packet inspection, a method commonly used by the Chinese government to block online content. With Chameleon in place, you can access the entirety of the internet without censorship and without giving up your identity.

VyprVPN offers a NAT firewall for all of its VPN plans. The company also stresses the importance of NAT firewalls for everyone who uses the internet, especially travelers and smartphone surfers.

VyprVPN also includes the following features:

  • Support for desktop operating systems, smartphones, and a variety of other platforms.
  • Incredible privacy features for the best VPN access in China and the Middle East.
  • Unlimited bandwidth and no restriction on P2P traffic or torrent downloads.
  • Zero-logging policy on both traffic and DNS requests.

Read our full VyprVPN review.

READER SPECIAL: All plans include a 30-day money back guarantee at only $5/month.


At this point, you should have a much clearer understanding of how NAT firewalls work to filter out unauthorized connections and protect your device from malicious attacks. We’ve recommended a few VPN providers which either offer turnkey firewalls built into their software, or which have other novel solutions which will offer the same level of protection or better.

What are your main cybersecurity worries? Do you use a configuration other than a NAT firewall or VPN to protect yourself? Leave your tips for our readers below.

How to get a FREE VPN for 30 days

If you need a VPN for a short while when traveling for example, you can get our top ranked VPN free of charge. ExpressVPN includes a 30-day money-back guarantee. You will need to pay for the subscription, that’s a fact, but it allows full access for 30 days and then you cancel for a full refund. Their no-questions-asked cancellation policy lives up to its name.

1 Comment

  1. it’s the universal case, no exceptions the higher the protection, the more the response time. though you’ll have to think of it as a trade-off. based on my major experience with the major ones like vypr, express, ivacy and even pure, if you’re adding to protection, you’ll have to be a bit patient because it has a cost attached to it since it adds more to the data you’re sending forth which would mean more time to encrypt and then decrypt at the other end.

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