What is a VPN firewall

A VPN and a firewall are two different cybersecurity tools often used together. A VPN encrypts internet traffic and hides IP addresses, while a firewall filters and controls incoming and outgoing network traffic.

Many people use the phrase VPN firewall when referring to a firewall protecting a VPN connection, a router with VPN and firewall capabilities, or VPN apps with built-in traffic filtering features. When combined, a VPN and firewall complement each other, improving online security. While a firewall protects your network from external threats, a VPN hides and secures the traffic traveling to and from your network.

For a more in-depth comparison of VPN and firewall, and how they work together, continue reading the article below.

🏷️ LIMITED OFFER: NordVPN deal! Get 75% OFF NordVPN + 3 months FREE 🏷️

What does a firewall do?

A firewall is a cybersecurity tool that creates a barrier between your device and external internet traffic. It monitors and filters traffic based on predefined security rules, blocking malicious activity and unauthorized access.

Firewalls are commonly used to block cyber threats and protect home and corporate networks. How they achieve this varies by their types:

• Packet filtering firewall – all data arriving at your network is divided into packets, which this firewall inspects on predefined rules, such as IP address, packet type, and port number. Since it only checks surface-level information, it’s fast and often used as the first line of defense.

• Stateful firewall – rather than inspecting data packets in isolation, this firewall assesses the context of active network connections. Context in this case refers to information about the origin and identity of data packets, such as IP addresses, sequence codes, destination addresses, and port data.

• Next-generation firewall (NGFW) – unlike traditional firewalls, NGFWs can inspect network traffic at several application layers, which allows for a deeper inspection. This makes them highly effective at spotting risky behavior, stopping complex attacks, and securing systems without slowing them down.

Firewall is the first line of defence against cyberattacks, which blocks malicious activities, prevents the spread of malware, and stops unauthorized access from exploiting your network. They do so by controlling external traffic coming into your network, not by encrypting data – that’s where a VPN comes into play.

What does a VPN do?

A VPN encrypts your data, hides your online activities, and masks your IP address. This protects your data from being monitored by ISPs, public Wi-Fi networks, or local administrators.

Privacy and security are especially critical on open networks, where hackers can easily intercept data, steal credentials, or deploy malware. Using a VPN helps you to make your data unreadable to hackers on the same network, thanks to encryption, which converts your information into a secret code. When you connect to a VPN, your IP address is replaced with the IP address of the VPN server. Connecting to a server in a different country can also be useful to bypass geographic restrictions that some websites or streaming platforms have.

How exactly your virtual private connection works is determined by the VPN protocol you use. A protocol is a set of rules that specifies how data is encrypted and moved within a VPN. It also affects the security and performance of your VPN connection. Below are some of the most popular modern VPN protocols:

• WireGuard - it’s the fastest VPN protocol available, thanks to its minimalist design made with relatively few lines of code. The modern algorithms it uses also provide a high level of security that no other protocol has beaten yet.

• OpenVPN – while not the fastest option, this protocol doesn’t compromise on security. It’s often preferred for higher customizability and higher-security environments.

• IKEv2/IPsec – this protocol stands out due to its speed, mobile-friendliness, and modern data scrambling method. It excels at switching between Wi-Fi and mobile data, ensuring stable connections.

VPN vs firewall: What is the difference?

In simple terms, firewalls monitor and filter traffic, while VPNs encrypt and hide it. Since these tools target different security problems, organizations often use them together. The table below might illustrate the differences between them better:

How VPN and firewalls work together?

Using VPN and firewall together provides enhanced protection against cyber threats. A firewall is the first line of defence, which filters traffic entering and leaving your network. It identifies malware and unauthorized access requests, promptly blocking any detected threats.

Meanwhile, VPN extends the protection outside the network. While users are browsing on the web, VPN hides their IP addresses and encrypt data, safeguarding their privacy and preventing tracking by ISPs, public Wi-Fi networks, or local administrators.

When combined, both cybersecurity tools complement each other, providing stronger protection against cyber threats. A firewall protects the network perimeter, while a VPN protects the data traveling through the network. Together, VPN and a firewall cover most of your basic network security needs. That’s why they’re often paired in real-world setups, such as corporate VPN behind a firewall, home router with firewall and VPN support, and VPN apps with a kill switch and traffic filtering.

Can a VPN bypass a firewall?

Sometimes, VPN traffic can pass through network restrictions because encrypted traffic looks similar to normal HTTPS traffic. VPNs with the OpenVPN protocol, using TCP port 443, have the highest chances of bypassing firewalls. Since the protocol has built-in obfuscation features, which are responsible for disguising VPN traffic as regular internet traffic, it can sneak through firewalls undetected.

However, VPNs can’t bypass all firewalls, especially in heavily restricted areas, as modern firewalls use deep packet inspection and can still detect and block VPN connections.

Types of VPN firewall setups

Different types of VPN firewall setups exist to address diverse security needs, ranging from individual privacy to securing multiple corporate networks. Below, I go into detail about the most common real-world VPN firewall setups:

• VPN behind a firewall – in this setup, the firewall protects the VPN server and blocks unauthorized connections. The firewall is configured to allow VPN traffic to the internal server while blocking all other unauthorized traffic.
• Firewall with VPN support – many routers and enterprise firewalls include built-in VPN functionality. In this case, the firewall handles filtering, encryption, and decryption without involving a second device, making the process simpler and faster.
• VPN software with firewall features – some VPN apps include kill switches or traffic filtering rules that act as a mini firewall. This approach is often found in consumer-focused VPN apps, like NordVPN or Surfshark.

Each approach protects network connections differently, so choosing the right one entirely depends on your security needs.

Benefits of using VPN and firewall together

The combination of VPN and firewall is widely used by companies, remote workers, and privacy-focused users, as it offers many benefits:

• Stronger protection against cyber attacks. A VPN alone can’t block all unauthorized access, and a standalone firewall can’t ensure data privacy through encryption. By combining them, they create layered protection where the VPN encrypts data in transit, and the firewall blocks unauthorized access, covering the most critical gaps in your cybersecurity.

• Encrypted internet traffic. While a firewall blocks unauthorized access to your network, it can’t prevent hackers from looking at your data during transit. A VPN comes into play here, scrambling your data, i.e., encrypting it and making it unreadable to anyone wanting to intercept it.

• Safer remote work access. A VPN allows employees to access the office server securely by encrypting data in transit. However, an already infected remote employee's device could spread a virus to the office via the encrypted VPN tunnel. Combining a VPN with a firewall mitigates this risk, as the firewall inspects traffic and can isolate the infected device from the rest of the internal servers.

• Protection against malicious traffic. A standalone VPN protects your data from prying eyes, but it can’t prevent malware from being installed on your device. Pairing it with a firewall solves this issue, as a firewall inspects VPN tunnel traffic, dropping the connection if it detects a threat.

• Improved privacy on public networks. On public Wi-Fi (like at airports or cafes), your data becomes vulnerable because it can be easily intercepted by hackers. Using a VPN on public networks improves privacy by encrypting your data, while a firewall blocks any malicious threats coming your way.

The combination of a VPN and firewall creates multi-layered protection, where the VPN improves data privacy and the firewall scans traffic for malicious threats, securing critical gaps in your cybersecurity.

Limitations of VPN firewalls

Even though VPN firewalls are effective at enhancing your privacy and security online, realistically, they can’t do it all – no tool can. A common misconception among users is that a VPN can guarantee complete anonymity online, but it can’t. While VPN provides improved privacy by hiding your IP address and traffic from ISPs and other onlookers, websites can still identify you through accounts, cookies, and browser fingerprinting.

Furthermore, firewalls alone can’t prevent all cyber threats. Hackers constantly find new ways to slip malware into your device that a firewall can’t stop, like clicking on a suspicious link received in your email. Your security ultimately depends on proper configuration and trusted software, and unless you have a Next-Generation Firewall (NGFW), malware can easily go undetected. Therefore, I encourage you to use reputable VPN providers in combination with secure firewall settings.

Conclusion

A VPN firewall combines two important security tools. Firewalls control network access and block malicious traffic, while VPNs encrypt internet connections and protect privacy. They both complement each other, securing critical gaps in your cybersecurity.

Using both technologies together provides stronger protection for home users and organizations, especially when accessing the internet through public networks or remote connections.