What is a firewall and how does it work?

What is a firewall?

A firewall acts as a 24/7 security guard, protecting networks from attackers. A firewall can be a hardware device or a software application. A firewall resides on a network and monitors and controls incoming and outgoing traffic within a set of security rules.

A firewall blocks cyber threats (such as DoS, DDoS, malware, or ransomware) lurking in the network, keeping it secure. Simply put, just as a security guard is needed to secure your home, a firewall is needed to secure your network.

What are the 5 components that a firewall monitors?

A firewall monitors 5 different types of components, including the flow of incoming and outgoing data packets. The firewall identifies these packets so that it can block them if they contain threats.

1. IP aur TCP headers: Here the firewall checks the IP and TCP headers to see if there are any unusual or malicious patterns in it.
2. HTTP request content: The firewall checks the content of incoming requests to ensure that no harmful content enters the system.
3. HTTP request frequency: In this, the firewall monitors the quantity and speed of incoming requests, so that attacks like Denial of Service (DoS) and Distributed Denial-of-Service (DDoS) can be detected.
4. HTTP response content: Along with incoming request data, it is very important for us to scan outgoing response data as well, so that if there is any malicious software in our system which is sending our data to other devices, then we can detect it.
5. Protocols: Here the firewall checks which protocols the data packets are coming from, so that packets that should be blocked by default are not allowed.

How Firewall Works?

1. Firewall inspects the data packets flowing between the incoming and outgoing network of the network.
2. Firewall compares the data flowing in the network with predefined security rules.
3. If the data packets match with these predefined rules, then the firewall allows them and blocks the data packets which do not match by considering them as malicious content.

Why Firewall Is Very Important?

Nowadays, firewalls secure the network and protect it from cyber threats, hence firewalls are considered the first line of Défense in cybersecurity. Firewalls monitor and filter the data traffic of the network. Firewalls have predefined rules, based on which the firewall can allow or block the data packets flowing in the network.

Firewalls are essential for securing networks these days. Because:

1. Just like a security guard looks after our house and prevents any unknown people from entering the house, similarly a firewall allows only trusted users and data to enter the network.
2. If any data contains viruses, malware or ransomware, or data from Distributed Denial-of-Service (DDoS) attacks, the firewall blocks that data before it reaches our system.
3. A firewall’s predefined rules and policies control network usage, such as parental controls, workplace restrictions, or government filtering.
4. If there are any suspicious and malicious applications or software inside the network, which are stealing the data of the system and network, then the firewall detects it and also reduces the insider risk.

Types Of Firewalls

Although there are many types of firewalls, here I will tell you about the 6 types.

1. Packet Filtering Firewall: This is a basic type of firewall, operating at the network layer. It regulates the flow of data packets between two networks. Firewalls of this type operate based on IP addresses, ports, and protocols. Packet filtering firewalls are generally faster, but they cannot detect advanced attacks.
2. Stateful Inspection Firewall: Stateful inspection firewalls continuously track the state of network connections. Their primary function is to ensure that only data packets pass through networks. Stateful inspection firewalls are considered very secure and reliable, making them widely used in networks today.
3. Proxy Firewall: A proxy firewall acts as a middleman, standing between the user and the Internet. A proxy firewall works at the Application layer of the OSI Model. This is why proxy firewalls are also known as application or gateway firewalls. A proxy firewall performs very deep inspection. Talking about its special feature, a proxy firewall also has its own IP address. The working process of a proxy firewall may be a little slow, but its work is very effective.
4. Next-Generation Firewall (NGFW): A Next-Generation Firewall (NGFW) is the most advanced network security device available today. While traditional, it also boasts numerous additional security features, making it much faster than other firewalls.
   • The main function of a Next-Generation Firewall (NGFW) is to monitor incoming and outgoing traffic. This firewall can also identify and allow or block specific applications. Additionally, this firewall has an Intrusion Prevention System (IPS), which allows us to detect and prevent real-time cyber-attacks.
5. Hardware Firewall: A hardware firewall is a physical security device installed between an internal network (such as PCs, servers, routers, etc.) and an external network or the Internet. The main function of a hardware firewall is to detect incoming data traffic before it enters the network or system. The main features of a hardware firewall include protecting not just a single device but an entire network.
6. Software Firewall: Software firewall is a software-based security program which can be installed on any individual device (like computer, laptop, mobile, server, etc.). Its main function is to monitor and control data traffic like a gatekeeper between the network or internet. This firewall works in conjunction with the operating system. Talking about its main features, this firewall can also control the applications, with the help of which the user can know which application is using the internet. With the help of this firewall any application can also be allowed or blocked.