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Hardware firewall: Protection against unauthorized access by third parties

A firewall is a special defense system that protects individual computers and entire networks from malicious access. Private users should have a so-called personal firewall installed for this purpose. Most companies or public institutions also rely on the protection of the hardware firewall in addition to the personal firewall. This is a separate device that can provide even more security.

The following text explores the question of what differences exist between the two types of firewall mentioned. However, it is also clarified which advantages a hardware firewall brings and when it makes sense to use it. Finally, of course, we also take a closer look at how it works.

What is a hardware firewall and what purpose should it serve?

A hardware firewall, often also called a network firewall or external firewall, scans the connection between two networks and restricts access. In doing so, it compares the sender and destination addresses and checks the services used. In addition, the current data traffic is examined and then a decision is made as to which elements are allowed through or blocked.

So far, the tasks of this firewall do not really differ from the personal firewall. We will now clarify exactly where the differences between the two systems lie.

What are the differences to the personal firewall?

Probably the biggest difference between these two protection systems is the existing components. The desktop firewall is a program that is installed on the computer to monitor the data traffic between it and the network. With some operating systems it is already available and does not necessarily have to be installed.

A hardware firewall, on the other hand, is a mix of software and hardware components. This hardware component is usually located between different networks and monitors the passing data traffic.

Simply put, the hardware firewall is a separate puttygen download device that regulates the data traffic between two networks. Software is also installed on it, and in some cases even its own operating system.

What are the advantages of the hardware firewall?

External firewalls are significantly more complex than desktop firewalls. This makes them more expensive in most cases, but they also make working on the Internet safer. Another big advantage is that the software does not run on the computers themselves. This means that it cannot be tampered with as easily as a desktop firewall, for example. If the latter are circumvented by hackers, the complete protection is lost.

Unfortunately, many users do not notice this and unknowingly catch computer viruses, Trojans and many other malicious programs. If this is attempted with a hardware firewall, the entire system is shut down directly. This will interrupt outbound traffic until the user reboots. The significantly higher security factor is also the reason why banks, for example, use a hardware firewall to protect their sensitive data in the best possible way.

In which areas is a hardware firewall used?

A hardware firewall is particularly important where very sensitive data has to be protected. Because it secures a network that operates on the Internet. In addition, a hardware firewall can also be used to connect several networks with one another and thus ensure a secure exchange of data. It can be set up individually with special software.

Since many of these devices also have a separate operating system, they are almost invulnerable to various external attacks. A so-called firewall appliance is also very often used. This is a completely finished and ready-to-use system made up of hardware and software. A distinction is made between these three types:

Which network zones can be set up with a hardware firewall?

The hardware component of the hardware firewall has various network interfaces (mostly between two and 20). The networks to be separated are connected to this and then divided into the following network and trust zones.

  1. The external network
    The external network is often referred to as a so-called WAN port. This is usually the Internet or a specific customer network. They are not considered to be particularly safe
  2. The internal network
    The internal network is often referred to as a LAN port and describes your own home network. This is usually secure and is assessed as trustworthy by the hardware firewall.
  3. The management network
    The management network is optional. It is used to configure the hardware firewall according to your own wishes, to define all rules and to manage the firewall.
  4. The demilitarized zone (DMZ)
    This network connection is also optional. This is where the accessible servers are housed, which cannot establish any or no sufficient connection to the Internet in the external network. However, the internal clients have the option of continuing to access these servers as well as servers from the Internet. This means that an intruder cannot directly influence the internal network. This also applies in the event that a server is taken from the external network.

What filter methods are there?

So-called packet filtering plays a very important role with the different types of hardware firewalls. An individually configured set of rules can be used to set which data packets are allowed through and blocked. The external firewall works on so-called OSI layers 3 and 4 (the switching and transport layers). Here, among other things, it also checks the individual packages for their properties in order to then decide how they are to be assessed (trustworthy or not trustworthy). Here, for example, exact IP addresses and ports are possible that were previously classified as permitted or blocked.

With the help of a so-called bridge or an extension called Switch, it is also possible to perform packet filtering on the second level of the OSI model (the data link layer). The starting point is not the IP addresses, but the MAC addresses that are used for hardware addressing.

Furthermore, after a certain extension, external firewalls can also filter the data packets using so-called state-based inspection methods (Stateful Packet Inspection, SPI). The application level and the data stored here are included here.

Which companies offer hardware firewall solutions?

There are some companies that offer hardware firewalls, such as:


With the use of a hardware firewall you can increase the security in the internal network, since the data traffic can be controlled more granularly than e.g. with a personal firewall. However, the hardware firewall is not worthwhile for everyone. Private users are adequately protected with the use of a personal firewall and do not have to spend the time operating a hardware firewall. Companies, on the other hand, should definitely think about using it.

Category: Firewall