What Does A Firewall Do?


A firewall is a security system that monitors and controls incoming and outgoing traffic on a network. It is used to protect a network from unauthorized access. A firewall can be either hardware- or software-based. Hardware-based firewalls are usually installed in routers. Software-based firewalls are usually installed on servers. A firewall can also be used to control access to websites and other online resources. For example, a firewall can be configured to block all traffic from a particular country or all traffic to a certain website.

What is a firewall?

In computing, a firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted internal network and untrusted external network, such as the Internet.

Firewalls can be hardware- or software-based. Hardware-based firewalls are usually incorporated into a router or other network devices. Software-based firewalls are usually installed on individual computers. Some firewalls can also be implemented as appliances, which combine hardware and software components.

Firewalls use a variety of techniques to control traffic, including packet filtering, application gateway, circuit-level gateway, proxy server, stateful inspection, and deep Packet Inspection (DPI).

How do firewalls work?

The primary function of a firewall is to keep unwanted traffic out of your network. Firewalls do this by inspecting each packet of data that comes into your network and comparing it against a set of rules. If the data packet is allowed according to the rules, the firewall forwards it on to the intended destination. If the data packet is not allowed, the firewall blocks it.

In order to keep up with the ever-changing landscape of security threats, firewalls are constantly being updated with new sets of rules. Many firewalls also have built-inIntrusion Prevention Systems (IPS) or Intrusion Detection Systems (IDS) which can detect and block known malicious traffic patterns.

The different types of firewalls

There are several types of firewalls that organizations can use to protect their networks. The type of firewall you choose will depend on your organization’s needs and budget.

Some common types of firewalls include:

  • Network Firewalls: These firewalls are hardware devices that sit between your network and the Internet. They inspect all traffic that comes in and out of your network, and can block or allow traffic based on pre-configured rules.
  • Application Firewalls: These firewalls are software programs that run on your servers and inspect traffic as it passes through them. Like network firewalls, they can block or allow traffic based on pre-configured rules.
  • Web Application Firewalls (WAFs): These firewalls sit in front of your web servers and analyze incoming traffic for malicious activity. If they detect an attack, they can block the traffic before it reaches your server.
  • Host-based Firewalls: These firewalls are software programs that run on individual hosts (e.g., computers, servers, etc.) and protect them from attacks coming from other hosts on the network.

    Choosing the right type of firewall for your organization is critical to ensure that your network is properly protected against threats.

Why you need a firewall?

A firewall is a critical piece of security hardware that helps protect your computer from outside threats. Firewalls can be used to block incoming traffic from specific IP addresses, ports, or even countries. They can also be used to limit outgoing traffic to specific destinations.

There are a few different types of firewalls, but the two most common are software firewalls and hardware firewalls. Software firewalls are installed on individual computers and act as a first line of defense against attacks. Hardware firewalls are usually installed at the network level and protect all devices on the network from threats.

Most home users will benefit from a software firewall, while businesses will generally need both a software and hardware firewall in place. No matter what type of firewall you choose, make sure it is always up to date with the latest security patches.

How to configure a firewall?

A firewall is a network security system that controls the incoming and outgoing traffic of your computer. It is important to configure your firewall correctly in order to keep your computer safe from malware and other attacks.

In most cases, you can configure your firewall through your router’s web interface. To do this, you will need to know the IP address of your router. This can be found in the documentation that came with your router or by doing a quick Google search.

Once you have the IP address of your router, open a web browser and enter it into the address bar. This will bring up the router’s web interface. From here, you will need to find the section for firewall configuration. This may be under a heading such as “Security” or “Advanced Settings”.

Within the firewall configuration section, you will need to specify which ports should be open and which should be closed. The specific ports that you need to open or close will depend on which applications you are using on your computer. Consult the documentation for those applications to determine which ports they require.

Once you have configured your firewall, be sure to save your changes and restart your router for the changes to take effect.

What are the benefits of using a firewall?

When it comes to cyber security, a firewall is one of the most important tools at your disposal. Firewalls can be used to protect your network from a variety of threats, including malware, hackers, and denial-of-service attacks.

There are many benefits to using a firewall, including:

  1. Protection from malware and viruses: Firewalls can help to block malicious software and viruses from infecting your network.
  2. Prevention of unauthorized access: Firewalls can prevent unauthorized users from accessing your network.
  3. Improved performance: Firewalls can improve the performance of your network by blocking unwanted traffic.
  4. Increased security: Firewalls add an extra layer of security to your network, making it more difficult for attackers to penetrate your system.

Are there any downsides to using a firewall?

There are a few potential downsides to using a firewall. First, if not configured correctly, a firewall can actually block legitimate traffic. Second, firewalls can sometimes slow down network performance because they need to inspect every single packet of data that comes through the network. Finally, firewalls can be bypassed if an attacker knows the right techniques.

How to choose a firewall for your business?

If you’re running a business, it’s important to keep your data and information safe from cyber attacks. One way to do this is by using a firewall. But how do you choose the right firewall for your business?

Here are a few things to consider when choosing a firewall for your business:

  1. What type of business are you running?
  2. How much data do you need to protect?
  3. How much money are you willing to spend on a firewall?
  4. Do you need a hardware or software firewall?
  5. What level of security does your business need?

    Answering these questions will help you narrow down your choices and find the best firewall for your business.


A firewall is one of the most important security features that any computer can have. By blocking incoming and outgoing connections, a firewall protects your computer from being compromised by malware or attackers. If you have a home network, be sure to enable the firewall on your router to help protect all of the devices on your network.

Mark Funk
Mark Funk is an experienced information security specialist who works with enterprises to mature and improve their enterprise security programs. Previously, he worked as a security news reporter.