Individuals and businesses must secure their information as the number of cybercrimes continues to rise. However, adopting the same presents numerous obstacles. A firewall is one type of security device that can help you protect your network and devices from outsiders. This tutorial on ‘what is a firewall’ will teach you everything you need to know about firewalls and how they work as a shield to safeguard your network. Explore some of the greatest cyber security courses available to improve your knowledge and skills in securing your information.

Now, let us begin by knowing what is firewall.

What Is Firewall?

A firewall is a network security device that monitors and filters incoming and outgoing network traffic in accordance with the security policies established by an organization. Essentially, it serves as a firewall between a private internal network and the public Internet.

Fencing your property secures your home and keeps trespassers at bay, just as firewalls secure a computer network. Firewalls are network security devices that prohibit unwanted access to a network. It can be a hardware or software unit that filters incoming and outgoing traffic within a private network using a set of rules to detect and prevent cyberattacks.

Firewalls are utilized in both business and personal environments. They are an essential part of network security. Most operating systems provide a simple firewall. However, employing a third-party firewall application offers greater protection.

How Does a Firewall Work?

As previously stated, firewalls filter network traffic on a private network. It determines whether traffic should be allowed or limited based on a set of rules. Think of the firewall as a gatekeeper at your computer’s entrance point, allowing only trusted sources, or IP addresses, to enter your network.

A firewall accepts just the incoming traffic that it has been set to receive. It distinguishes between legitimate and malicious traffic and allows or blocks particular data packets based on predefined security rules.

These rules are based on numerous factors of the packet data, such as the source, destination, content, and so on. They block traffic from dubious sources to prevent cyberattacks.

For example, the image depicted below shows how a firewall allows good traffic to pass to the user’s private network.

However, in the example below, the firewall blocks malicious traffic from entering the private network, thereby protecting the user’s network from being susceptible to a cyberattack.

This way, a firewall carries out quick assessments to detect malware and other suspicious activities.

There are different types of firewalls to read data packets at different network levels. Now, you will move on to the next section of this tutorial and understand the different types of firewalls.

Types of Firewalls

A firewall may be either software or hardware. Software firewalls are programs that run on each computer that govern network traffic using apps and port numbers. Meanwhile, hardware firewalls are the devices that stand between the gateway and your network. You also refer to a firewall offered by a cloud service as a cloud firewall.

Firewalls are classified into different sorts based on how they filter traffic, their structure, and operation. There are several types of firewalls, including:

• Packet Filtering

A packet filtering firewall controls data flow to and from a network. It allows or blocks the data transfer based on the packet’s source address, the destination address of the packet, the application protocols to transfer the data, and so on.

• Proxy Service Firewall

This type of firewall protects the network by filtering messages at the application layer. For a specific application, a proxy firewall serves as the gateway from one network to another. 

• Stateful Inspection

Such a firewall permits or blocks network traffic based on state, port, and protocol. Here, it decides filtering based on administrator-defined rules and context. 

• Next-Generation Firewall

According to Gartner, Inc.’s definition, the next-generation firewall is a deep-packet inspection firewall that adds application-level inspection, intrusion prevention, and information from outside the firewall to go beyond port/protocol inspection and blocking.

• Unified Threat Management (UTM) Firewall

A UTM device generally integrates the capabilities of a stateful inspection firewall, intrusion prevention, and antivirus in a loosely linked manner. It may include additional services and, in many cases, cloud management. UTMs are designed to be simple and easy to use.

• Threat-Focused NGFW

These firewalls provide advanced threat detection and mitigation. With network and endpoint event correlation, they may detect evasive or suspicious behavior.

What Are the Benefits of a Firewall?

The value of firewalls as a critical line of defense in cyber security cannot be overstated. For decades, firewalls have served as a primary barrier, protecting networks and devices from possible attacks. Their major function is to provide a barrier between secure internal networks and potentially untrustworthy external sources.

In today’s interconnected business landscape, businesses are more vulnerable than ever to possible dangers. Cyberattacks are not limited to downtime or data breaches. They can dramatically harm an organization’s reputation, lose trust, and result in financial consequences. For organizations, firewalls secure data and prevent illegal access.

Furthermore, as business ecosystems change and integrate, the digital perimeter of an organization grows. This enlargement creates more surface area for possible attacks. Firewalls help to monitor and regulate data flow by allowing approved data while blocking harmful or unintended data. This control is critical for enterprises because they must assure data security while maintaining efficient operations.

Read Also: Top 5 Cybersecurity Mistakes Businesses Make

The strategies used to defend enterprises should evolve with the times. While classic firewalls provide basic protection, recent improvements have resulted in even more advanced features to address today’s complex digital environments and security systems.

Next-Generation Firewalls (NGFWs) are the modern answer for digital security, with more complex varieties, such as ML-powered NGFWs, to stay up with the current threat landscape. Firewall evolution combines the greatest aspects of historic technology with today’s revolutionary technologies, providing improved network security by combining the strengths of classic technology with contemporary developments.

Monitoring and Filtering Network Traffic

A firewall’s primary role is to oversee all data packets that traverse a network. Stateful inspection firewalls play a significant role in this oversight by monitoring active connections, noting the state and attributes of every data packet, and ensuring nothing slips through unnoticed. 

They act as an initial barrier, filtering incoming information to detect potential threats. Monitoring network traffic prevents harmful data or patterns from entering the system, maintaining the security of the internal network. 

Preventing Virus Infiltration

Viruses constantly evolve, requiring sophisticated countermeasures. Firewalls, in tandem with antivirus software, serve as an effective barrier against these threats, including various forms of malicious software. 

For example, packet filtering firewalls examine each data packet’s headers, allowing or blocking them based on set criteria. By analyzing these packets, firewalls can discern malicious patterns associated with known viruses, thereby neutralizing them before they breach the system. 

The advent of next-generation firewalls (NGFW) has introduced a higher scrutiny level. These advanced firewalls incorporate traditional mechanisms with newer features, catching and neutralizing even the most advanced viruses.

Blocking Unauthorized Access

With the increasing reliance on digital platforms and private networks, unauthorized access attempts have become more frequent and sophisticated. Firewalls operate as vigilant gatekeepers, overseeing all entry points, preventing hacking, and ensuring that only authorized users can access vital system resources. 

Network firewalls play a pivotal role in this, acting as lookouts that oversee all access points within a network. By leveraging access control mechanisms, these firewalls ensure that only trusted sources can communicate with the system. 

Upholding Data Privacy

In today’s digital landscape, data privacy is paramount. By scrutinizing every piece of data that enters or leaves a network, firewalls prevent unauthorized access and ensure private data remains confidential. As businesses hold vast amounts of sensitive information, from personal details to financial data, the role of firewalls becomes even more pivotal. With security rules and access control measures, firewalls shield data from external threats and ensure businesses can operate in a secure digital space.

Supporting Regulatory Compliance

For many organizations, especially those in regulated industries, adherence to data protection standards isn’t just about securing data—it’s a legal requirement. Firewalls play a dual role in this context. 

They enforce stringent data protection measures by controlling and logging access to sensitive data, ensuring that only authorized individuals can access and modify critical information. Firewalls also maintain comprehensive logs of these activities, which is a crucial feature for audit trails. When regulators or internal auditors need evidence of security measures and activity histories, these logs become invaluable. 

By ensuring data integrity and providing verifiable logs, firewalls assist organizations in maintaining compliance, thereby preventing potential legal complications, and ensuring continued trust from stakeholders.

Enhanced User Identity Protection

Modern firewalls offer precise identification of users regardless of location, device, or operating system. This ensures that security policies are aligned with business needs, granting or denying access based on user identity and not merely IP addresses. Such granularity in control facilitates a safe environment where specific tasks can be permitted to certain user groups, further refining the security landscape.

Control Over Application Use

With the evolving digital workspace, users engage with a variety of application types. More sophisticated products have the ability to accurately identify and control these applications, ensuring that only sanctioned or tolerated apps are accessed. This aids in maintaining security while allowing flexibility in application usage based on business requirements.

Encrypted Traffic Security without Privacy Compromise

With the rise in encrypted web traffic, advanced firewalls provide a mechanism to decrypt malicious traffic while preserving user privacy. This allows organizations to scrutinize potential threats without infringing on user rights or hampering performance.

Advanced Threat Protection

The increasing sophistication of cyber threats calls for advanced security devices and mechanisms. Many modern firewall products provide integrated solutions that coordinate intelligence across various attack vectors, ensuring comprehensive protection against both known and novel threats.

Automated Threat Intelligence Sharing

The sheer volume of threat data can be overwhelming for organizations. Some variations of current firewalls automate the process of threat detection, analysis, and response, pooling insights from a global community and ensuring swift security updates.

Zero Trust Principles

Traditional security models are perimeter-centric, potentially leaving internal threats undetected. The Zero Trust approach inherent to more advanced firewalls requires constant validation and authentication for any action within the network infrastructure. This method ensures that every potential threat, whether internal or external, is identified and mitigated.

How to Use Firewall Protection?

To keep your network and devices safe, make sure your firewall is set up and maintained correctly. Here are some tips to help you improve your firewall security:

• Constantly update your firewalls as soon as possible: Firmware patches keep your firewall updated against any newly discovered vulnerabilities.
• Use antivirus protection: In addition to firewalls, you need to use antivirus software to protect your system from viruses and other infections.
• Limit accessible ports and host: Limit inbound and outbound connections to a strict whitelist of trusted IP addresses. 
• Have active network: To avoid downtime, have active network redundancies. Data backups for network hosts and other critical systems can help you avoid data loss and lost productivity in the case of a disaster.

Bottom Line

In this tutorial on what is a firewall, you learned what it is and how it works. You also learnt about several types of firewalls and how to utilize one. Cybersecurity is a rapidly growing field in today’s world. If you want to learn ethical hacking to keep devices and networks safe from cybercriminals. In such situation, Simplilearn’s Cyber bootcamp, CEH v11 – Certified Ethical Hacking Course, will teach you sophisticated network packet analysis and penetration testing techniques to help you improve your network security skills.

Firewalls are used in a variety of settings, including homes, businesses, data centers, and other networked systems, to protect them from unwanted access and potential cyber threats.

The most appropriate firewall type is determined by the specific requirements and situation. For home users, a software firewall or the built-in firewall on a router may be sufficient. In enterprise environments, a combination of firewall types such as packet filtering, stateful inspection, and application-layer firewalls may be employed to provide comprehensive security. The optimal firewall relies on your security requirements, price, and network complexity.