What is a Firewall? Everything you need to know about

In order to protect your computer, you need to install a firewall. It is commonly used in conjunction with anti-malware software to prevent illegal access to your computer network. If you’ve set up security rules, you can send and receive information without restriction. Any incoming traffic that doesn’t adhere to these guidelines is automatically denied entry. In this way, undesirable traffic is reduced, and more resources are made available for real data transmission.

A firewall might be likened to an electric fence that serves as an additional layer of security against criminals and suspicious individuals.

The fundamental function of a firewall is to protect an internal network from outside intrusions. This prevents harmful communications from reaching the systems that are linked. What role does a firewall play in all of this?

Summary of the firewall history

The first, second, and third generations of firewalls have all been developed to date.

In 1988, “packet filter firewalls,” or “first-generation firewalls,” were established. They were created by Digital Equipment Corporation engineers. A workable first-generation firewall concept was built by Bill Cheswick and Steve Bellovin, who worked together. Packets were scrutinised as they passed from one computer to another across the Internet. If the packet filter’s rules are met, the packet will be refused and the sender will get an error message.

It was between 1989 and 1990 when second-generation firewalls were introduced. Employees of AT&T Bell Laboratories, Dave Presetto, Janardan Sharma, and Kshitij Nigam, came up with the first one. When it came to computers and networking, these were known as “circuit-level firewalls.”

Internet Engineering Task Force (IETF)-approved third-generation firewalls are also in use today (IETF). They are far more user-friendly than their predecessors. You don’t need to know how to code to set them up.

In the late 1980s, the word “firewall” was initially used to describe a network security device.

Definition of Firewalls

Incoming traffic is analysed by firewalls according to predefined rules. These rules are used to filter traffic. As a result, any incoming communication that is unwelcome, unknown, or suspicious is blocked. Main ports and entrance points to a network are the focus of the investigation.

Imagine a computer network as a house to better grasp the concept. Connected gadgets can be found in the various rooms of the residence. Entrance points are the firewall-protected doorways. All rooms in this home can only be accessed by the people who live there, to use an analogy. The firewall will prevent guests from accessing the restricted areas if the homeowners decide to have a party there.

Features of Firewalls

In today’s world, most people expect their firewalls to offer the following basic capabilities.

Simple to Take Care of

For the most part, corporate networks are elaborate affairs with several parts and the ability to accommodate a large number of devices. Since they store so much sensitive information, they need to be protected from the widest possible range of online threats. System and network administrators should appreciate how much easier firewalls have become in recent years. Ideally, they should be able to work with most, if not all, existing security systems and provide monitoring and management through a single interface.

Threats Can Be Prevented

The purpose of firewalls is to safeguard a network. Given today’s ever-increasing danger landscape, this has become increasingly critical. They must be able to recognise and block any potential dangers before they can reach the network. Anti-phishing, anti-malware, anti-bot, and the capacity to be fed with high-quality threat information feeds should be basic threat prevention capabilities included in firewalls.

Capable of handling applications with a wide range of granularity and access restrictions

For each application, there are its own rules and regulations. Some traffic may need to be prioritised, while others may need to be prohibited from accessing the Internet. It should be possible for firewalls today to determine which applications need what and alter their operations accordingly.

Employees are not all granted the same amount of access to the company’s resources. Executives and managers have access to more resources and information than the rest of the workforce, for example. A firewall should be able to restrict access to certain resources depending on a user’s job title or position within the organisation.

Is able to run cloud-based software and services.

Cloud computing is currently used by nearly all businesses. And they don’t generally stick with just one supplier. Your firewall should be able to determine which policies to enforce in which environment to provide the same degree of security across the network, including cloud apps and services. Even more so if the cloud service provider is not responsible for protecting your data.


Companies may simply add or remove resources from their networks with cloud computing. Their firewalls must also be able to handle these modifications. No matter what resources are added or removed, all connections must be safeguarded from cyber threats. ‘

Types of Firewalls

There are a variety of firewalls to choose from, just like there are a variety of technologies to choose from. Here are a few of them:.

1. Next-Generation firewall (NGFW)

Additional functionality like intrusion protection, encrypted traffic inspection, antimalware, and more are included in an NGFW. DPI is also used, allowing users to determine, categorise, and block malicious-data-carrying packets from entering the internal network by analysing the data contained within each packet.

2. Firewall proxy

A proxy firewall, on the other hand, protects software and its users from hazardous communication by filtering traffic at the application level. When two systems communicate through a proxy, one must first make a request to the other in order for that communication to take place. As a general rule, a proxy firewall analyses HTTP and FTP traffic for suspicious activity.

3. Network Address Translation (NAT)

Network address translation (NAT) firewalls allow numerous devices with different network addresses to share a single IP address and connect to the Internet. In this way, all users are able to hide their IP addresses. If an IP address is blocked by a NAT firewall, hackers will have a far more difficult time finding one to attack with.

4. SMLI firewall.

At the application layer, SMLI firewalls are responsible for enforcing policies on network traffic. They do this by comparing newly received packets to previously received ones. As NGFW firewalls do, they examine all packets and only allow access to those that pass inspection, making them very comparable to traditional firewalls.