A hardware firewall is a stand-alone physical device placed in the network to filter internet traffic. All computer network exchanges happen with data packets being checked with a firewall, enforcing security policies and access controls. Much like a server or a computer, the device is autonomous and dedicated to the sole function of connection inspection.

As a hardware firewall is self-contained, it has all the necessary hardware and computer software components to enforce network security boundaries. The exact features and mode of operation can heavily depend from one hardware firewall to the other, but it generally provides at least a URL filtering and intrusion prevention system (IPS).

How does a hardware firewall work?

Hardware firewall examines the data flowing in from the internet, verifying that it doesn't breach security policies. Packet filters analyze the exchanged data by checking its various attributes like source and destination IP addresses, used port numbers, etc. Then, the gathered data is compared to various permissions determining whether the internet traffic should be blocked.

Hardware firewall scheme

Most hardware firewalls also apply additional access controls and security inspection features. Some go as far as integrating machine learning algorithms to identify malicious content types or enforce signature detection solutions. These technologies are bundled together and work in tandem to reinforce the protection against cyber threats.

One particularity of a hardware firewall is that as physical appliances, their setup, for the most part, can be plugged and played. They're pretty effective at covering the entire network by being deployed in inline mode. All the network devices can be protected without any additional input needed to configure them, which makes network security administrators' work and maintenance easier.

Examples of hardware firewalls

Generally speaking, hardware firewalls aren't that different from any other device equipped with a software firewall. The emphasis is that a separate device is allocated solely to inspect the network traffic. As for their types, all firewalls are either stateful or stateless. The latter focuses only on individual data packets using preset rules, while the former can monitor and detect all internet traffic states.

In particular, hardware firewalls can be built-in a router or come as a separate gadget. Such devices have onboard memory running security policies, executing business rules, and routing network traffic. The devices themselves can range from a small tablet device to a large server. Though firewalls rarely are used on their own, an organization likely combines hardware devices with security software to lower potential cyber risks.

Advantages of physical firewalls

Internet security is an important aspect of most organizations' agenda, so a significant emphasis is based on its choice. However, there are numerous advantages that a hardware firewall provides.

1. Default rules for all network devices

When each user has a software firewall on their device, it makes it very difficult to ensure that each of them has identical settings enabled. Furthermore, this removes the administrators' control as users may fiddle with the settings or deactivate them. A hardware firewall implemented on the network provides a consistent level of security throughout the whole network. As filtering is applied to each gadget on the network, a hardware device makes this much easier.

2. Additional processing power for remaining devices

Network security system without a hardware firewall means installing a software solution on either endpoints or the server. This means that computing power and memory are used for network traffic analysis, which can severely affect the device's performance. In contrast, a hardware firewall runs on its proprietary hardware, meaning the remaining network devices have more memory and processing power available for other work-related tasks.

3. Simple management

Firewalls must be consistently maintained to ensure that they perform their functions. While it wouldn't be practical to check up on each user's software firewall manually, a single hardware firewall is much easier to maintain. All necessary upgrades can be added instantly and become active on all devices on the network instantly. This covers devices that don't traditionally support firewalls, like IoT.

4. More resistance to cyberattacks

Having dedicated hardware allocated just for firewall functions means the firewall system is somewhat isolated from other threats. As most malware is written to disrupt computers, having a firewall set up on one makes it at the forefront of the attack. On the other hand, when a firewall exists on a separate hardware device, it's much easier to protect from an attack targeting underlying operating systems to exploit them.

5. Better network visibility

Fragmented cybersecurity solutions can leave blind spots that hackers could exploit. This can hurt network visibility and make it much harder to deter various cyber threats. A homogenous cybersecurity solution doesn't need to absorb data from various scattered sources. As monitoring occurs from within the network, a hardware solution can provide a much better network awareness centralizing everything happening within a network. IP address source inspections and other functionalities are also performed.

Disadvantages of physical firewalls

Hardware firewalls aren't the be-all and end-all solutions for all potential cybersecurity problems. While they bring benefits, this solution itself has some traits that might be a dealbreaker for your organization.

1. Higher cost

Hardware firewalls are a combination of both physical devices as well as software. It should be no surprise that this setup is much more expensive than the alternatives. These specialized computers can quickly crunch large volumes of internet traffic, so the faster the processing speed, the more they cost.

2. Difficult to set up

The trouble with setting up a hardware firewall begins with the fact that it's a physical device. It needs to be carried and connected to the mainframe taking up precious physical space. The second part of the trouble comes from software configurations to make it work within the network. This can be complicated if a hardware firewall is set up to protect remote employees, as various workarounds will be needed.

3. Limited inspection directions

Unlike other firewall types, hardware firewalls can inspect only incoming internet traffic by default. This may help secure against various cyber threats targeting the network boundary of your perimeter, but it can't help when trying to block traffic from your network. This leaves your organization susceptible to various exfiltration attacks.

4. Difficult maintenance

Hardware firewalls are notoriously difficult not only to set up. Maintenance can also be very difficult, and network administrators may need to rotate to provide 24/7 support. In some cases, the maintenance will need to be performed on-site. The updates, as well as various other configurations and adjustments, won't be as streamlined as with other firewall solutions.

Hardware vs. software firewalls

Hardware firewalls are contained within a single physical device that's inserted into the network. On the other hand, a software firewall is a program installed on individual devices. While their functions overlap, the execution of each solution is very different.

For instance, hardware firewalls filter traffic from the uplink toward enterprise endpoint systems. That way, they insert themselves between the public internet and the organization's network. In contrast, firewall software analyzes traffic that has already passed through the uplink into the client but hasn't yet been accessed. This means that a software firewall allows threats much closer to the network.

Another key difference is that hardware firewalls have both memory and onboard storage to enforce security policy rules. Meanwhile, a software firewall completely depends on the client it's installed on. If it's a user's device, this solution may consume a significant portion of online bandwidth and processing power. Having a separate physical unit in a server makes network boundary enforcement much more efficient.

Is a hardware firewall better than software?

Both hardware and software firewalls perform very different functions. As they perform them in very different ways, this also means that they have very different sets of advantages. If an organization is cautious about the space, has a limited budget, or needs an easy setup, then a hardware firewall isn't a good choice. Software firewalls are more flexible, cheaper, and easier to maintain, while they come with security limitations.

A firewall choice should depend on business needs, picking an option that compliments the rest of the security setup (like a used VPN service). Though, one of the most common tactics for large network supervision is having hardware and software firewalls deployed to create several layers of security. The way enterprise-level hardware firewalls can coexist with basic firewall capabilities provided by simpler endpoint solutions.