Firewall vs. VPN: Which one to use and when?

What is a firewall?

A firewall is a security system that establishes a barrier between an internal network and untrusted networks, like the internet. This barrier then filters network traffic according to pre-established security rules.

Organizations use firewalls to protect their networks from unauthorized access and other security risks. A firewall blocks malicious activities and limits what users from within the network can connect to.

Types of firewalls

There are three main ways to categorize firewalls. The first one reflects how users set up the firewall.

• Hardware firewalls represent firewalls hosted on a separate piece of hardware.
• Software firewalls are programs installed on every host device that needs protection.
• Cloud-based firewalls are delivered on demand over the internet by a software-as-a-service provider.

The second categorization takes into account the way a firewall operates.

• Packet-filtering firewalls check the headers of data packets to see if they conform to the criteria for passing through.
• Application-level gateways are also known as proxy firewalls. They use a proxy server to conceal internal IPs while scanning client requests for potential threats.
• Stateful inspection firewalls maintain a database of familiar packets to let known traffic pass faster next time.
• Circuit-level gateways establish a virtual network to validate traffic based on handshaking protocol and pre-set rules.
• Next-generation firewalls (NGFW) supplement traditional firewalls with advanced cybersecurity features. For example, NGFW detects and blocks malware.

The next step for the NGFWs is utilizing artificial intelligence (AI) and machine learning (ML) technology. AI and ML-powered next-generation firewalls can proactively detect potential threats to the private network.

What is a Virtual Private Network (VPN)?

At the other end of the firewall vs. VPN comparison, we have Virtual Private Networks (VPNs). VPN is a network privacy and security tool that protects your personal details by routing traffic through a remote server.

When you connect to a VPN server, it hides your real IP address by assigning a new one. VPN service can also perform multiple other functions.

• Data encryption. A VPN encrypts all your data to ensure online privacy.
• Hiding online activity from ISP. Your Internet Service Provider (ISP) can see everything you do online. When using a VPN, the ISP only sees the encrypted version of traffic.
• Accessing intranets remotely. You can safely access your organization’s intranet from elsewhere with a remote access VPN.
• More secure connection on public networks. VPN increases security when you connect to a public network.

These are the primary examples of broad functionality some VPN services offer.

Types of VPNs

There can be many typologies and types of VPN services. Just like with firewalls, there are hardware VPNs and software VPNs.

Additionally, knowing the following four types comes in handy for a VPN user:

• Site-to-site VPN. Companies with multiple locations use this type of VPN to establish secure connections. Businesses also use site-to-site VPN to connect with a partner firm’s intranet.
• Remote access VPN. Employees use remote access VPNs to connect to the firm’s private network from home or elsewhere. Private users also gain access to regional content with this type of VPN.
• Mobile VPN. This VPN enables mobile users to access private networks on the go.
• Cloud VPN. This VPN connects users to cloud-based infrastructures.

One can also categorize VPNs based on the VPN protocol they use for encryption. For example, this would mean distinguishing between IKEv2 VPN and WireGuard VPN.

Firewall vs. VPN comparison

After laying out the main types and features of the two security tools, the firewall vs. VPN comparison becomes straightforward. The two perform different network security functions.

• A firewall protects your network from outside threats.
• VPN protects your traffic as it travels to and from your network.
• Firewalls detect and block malware, protecting your devices and networks from damage.
• Firewalls check whether connection requests to and from the network comply with its rules.
• VPNs hide your IP address to boost the privacy of your connections.
• By encrypting your traffic, VPNs protect the privacy of your online activities.

Thus, a firewall in cybersecurity is like customs monitoring what can go in and out of the country. It ensures that only authorized people pass through and stops all malicious activity.

Meanwhile, a VPN is responsible for security when you “go abroad” from your network. It ensures you travel privately and helps bypass the obstacles on the road.

VPNs and firewalls: Friends or foes?

Firewall vs. VPN can sound like an actual battle due to some opposing functions these tools perform. Firewalls monitor traffic, while VPNs aim to hide it. Firewalls are barriers restricting access, while VPNs help to access content safely without interruptions.

However, the relationship between the two goes beyond this firewall-vs-VPN cat-and-mouse game. As cybersecurity solutions, they complement each other.

From the perspective of an organization, using both is a good idea. A firewall protects the intranet from outside threats and helps ensure regulatory compliance. Unauthorized users cannot pass through a well-set-up firewall.

Meanwhile, a VPN enables authorized users to connect to the intranet remotely. Thus, employees can work remotely and access all company resources. Similarly, a VPN lets students access their university’s databases from home or elsewhere.

To summarize, firewall vs. VPN is a false dilemma if we imagine we must choose only one. Organizations have good reasons to use VPNs and firewalls in combination. The two tools perform different functions to ensure cybersecurity and business contingency.