Firewalls control and regulate the flow of data between networks. Firewalls are a primary security measure on public networks, created with predetermined parameters to prevent unauthorized access or from occurring. A firewall serves like a barrier separating a public network from a private one-somewhat like two rooms separated by an imaginary wall.

Computers and the internet are vulnerable to cyberattacks, and a firewall is needed to protect data from unauthorized networks. A firewall can be incorporated either as software or as a hardware device, and the combination of both functions helps filter network traffic.

An exceedingly important piece of a network framework is the firewall. Firewalls are often used to protect computers from outside threats and viruses while also safeguarding privacy by restricting a person’s access to the internet.

Firewalls are used to filter traffic in devices on a network. They separate the public from private networks (or allow them), and protect against malicious packets.

Nowadays, all electronic devices which can access the internet should have some type of firewall because these devices can be affected by a malicious packet that will destroy its security.

A firewall can manage a number of different functions, including:

  • Defend resources
  • Manages and control network traffic
  • Validates access
  • Records
  • Reports on events
  • Take action immediately

What will we learn?

  • Functionality
  • Types
  • Proxy-based firewall
  • Stateful firewall
  • Web application firewalls
  • Next-generation firewalls
  • Hardware and Software
  • Software firewall
  • Hardware firewall
  • Firewall Techniques
  • Packet filter
  • Application gateway
  • Circuit-level gateway
  • Proxy Server
  • History
  • Common Issues and Solutions


A firewall creates a barrier between the exterior world and your secure network, like an actual fire extinguisher. If the system identifies an incoming packet, and it has been blocked by the firewall, then this packet will not be allowed to go through. A firewall is a system that filters out traffic.

Types of Firewall

Firewalls are created to control the flow of data in and out of your network. They operate at different levels, depend on what you’re doing, and with whom you do it.

The following is a brief overview of the different types of firewalls:

Proxy-based firewall

The proxy-based firewall works as an intermediary between the end user and data. This type of firewall is a gateway for all connected devices and divides the connections to the source of data.

Proxy-based firewalls filter data packets and implement policies that mask the recipient devices location, protect the recipient network and device.

Stateful firewall

This type of firewall records the track of information about connections and makes it compulsory for the firewall to check every packet. By watching packets, firewalls can mitigate delay. A Stateful firewall simply inspects network traffic and determines whether one data packet is related to another on or not.

Web application firewalls

Web application firewalls protect servers that support web applications and also serve as a firewall for the Internet. They mainly do this by examining whether each client trying to reach the server should be given access.

Next-generation firewalls

A next-generation firewall prevents individual applications and users from accessing certain data on a network, in many cases based on the source port number. Firewalls of this type took years to develop, becoming more progressively complex as they allow or block traffic.

Hardware and Software

Software firewall

A software firewall can protect your electronic device from data breaches. It blocks programs on your local network or the Internet and you can configure it easily to do this.

Hardware firewall

Routers have a firewall feature that you can set up on the Firewall settings page or configure manually.

Firewall Techniques

There are multiple types of firewall techniques.

Packet filter

The packet filter is designed to detect and inspect the packets coming in or going out of a network. They are considered efficient when inspecting unauthorized packets, but they can be difficult to set up if compared with other approaches.

Application gateway

An application gateway is an effective way of implementing security, but it leads to a performance decrease.

Circuit-level gateway

If a Circuit-level gateway is applied to the Application level, packets can flow between hosts without checking on a more granular level. If this application gateway already applies security mechanisms (UDP or TCP), then no further inspection takes place.

Proxy server

This firewall technique blocks outgoing and incoming information from the network, making it difficult to identify the true network address. Basically, firewalls consist of two or more of these firewall techniques.

Firewalls have lots of importance in ones daily life, both for your device and your data. A firewall helps to block malicious programs from infecting a system or damaging data. Additionally, the firewall prevents potential Trojan horses and malware from attacking the system without endangering privacy.


The term firewall originated in the late 1880s and was used to refer to network technology. The internet of that era had only a small audience, so firewalls protected buildings from fires. Routers were precursor technologies and replaced firewalls by the late 1980s.

Common Issues and Solutions

Every user is vulnerable to having their privacy invaded. When this happens, your PC starts working too slowly or freezes.

Here are some solutions to resolve the common issues:

  • Broadband internet access provides a steady connection at home.
  • Connecting to public Wi-Fi can be unsafe as others may be able to access your connection.
  • Set up a home network that is safeguarded from the internet.

For these security needs, a personal firewall can be configured so that the user can customize their security settings as needed.