What Is a Firewall: Everything You Need to Know

 A Firewall is a network security device that monitors and filters incoming and outgoing network traffic based on an organization’s previously established security policies. At its most basic, a firewall is essentially the barrier that sits between a private internal network and the public Internet. Firewalls’ primary purpose is to allow non-threatening traffic in and to keep dangerous traffic out.

History of the firewall

Firewalls have existed since the late 1980s and began as packet filters, network devices configured to examine packets (or bytes) transferred between computers. Although packet-filtering firewalls are still in use today, they have evolved significantly over the decades.

Types of firewalls

• Proxy firewall
• Stateful inspection firewall
• Unified threat management (UTM) firewall
• threat-focused NGFW
• Virtual firewall

Proxy firewall

An early type of firewall, a proxy firewall acts as a gateway between networks for a specific application. Proxy servers can provide additional functionality, such as content caching and security, by intercepting and filtering traffic before it reaches the destination. However, this may also impact throughput capabilities and the applications they can support.

Stateful inspection firewall

Not considered a “traditional” firewall, a stateful inspection firewall allows or blocks traffic based on state, port, and protocol. It monitors all activity from the opening of a connection through its closure. Filtering decisions are made based on administrator-defined rules and context, which uses information from previous connections and packets belonging to the same connection.

Unified threat management (UTM) firewall

A UTM device typically loosely integrates the functions of a stateful inspection firewall, intrusion prevention, and antivirus. It may also include additional services and often cloud management. UTMs focus on simplicity and ease of use.

Next-generation firewall (NGFW)

Firewalls have evolved beyond simple packet filtering and stateful inspection. Most companies are deploying next-generation firewalls to block modern threats, including advanced malware and application-layer attacks.

According to Gartner, Inc.’s definition, a next-generation firewall must include:

• Standard firewall capabilities, like stateful inspection
• Integrated intrusion prevention
• Application awareness and control to see and block risky apps
• Upgrade paths to include future information feeds
• Techniques to address evolving security threats

While these capabilities are increasingly becoming the standard for most companies, NGFWs can do more.

threat-focused NGFW

Additionally, these firewalls include all the capabilities of a traditional NGFW and provide advanced threat detection and remediation. With a threat-focused NGFW, you can:

• Know which assets are most at risk with complete context awareness
• Quickly react to attacks with intelligent security automation that sets policies and hardens your defenses dynamically
• Better detect evasive or suspicious activity with network and endpoint event correlation
• Significantly reduce the time from detection to cleanup by continuously monitoring for suspicious activity and behavior in retrospective security, even after initial inspection.
• Streamline administration and reduce complexity with unified policies that protect the entire attack continuum.m

Virtual firewall

A virtual firewall is typically deployed as a virtual appliance in a private cloud (VMware ESXi, Microsoft Hyper-V, KVM) or public cloud (AWS, Azure, Google, Oracle) to monitor and secure traffic across physical and virtual networks. It is often a key component in software-defined networks (SDN).

What exactly do firewalls do?

A Firewall is a necessary part of any security architecture. It takes the guesswork out of host-level protections and entrusts them to your network security device. Firewalls, especially Next-Generation Firewalls, focus on blocking malware, application-layer attacks, and an integrated intrusion prevention system (IPS).

These Next-Generation Firewalls can react quickly and seamlessly to detect and react to outside attacks across the whole network. They can set policies to defend your network better and carry out quick assessments to detect invasive or suspicious activity, like malware, and shut it down.

Why Do You Need Firewalls?

Firewalls, especially Next-Generation Firewalls, focus on blocking malware and application-layer attacks. Along with an integrated intrusion prevention system (IPS), these Next-Generation Firewalls can react quickly and seamlessly to detect and combat attacks across the whole network.

Firewalls can act on previously set policies to better protect your network. They can carry out quick assessments to detect invasive or suspicious activity, such as malware, and shut it down. By leveraging a firewall for your security infrastructure, you’re setting up your network with specific policies to allow or block incoming and outgoing traffic.

Firewalls can also be used for content filtering. For example, a school can configure a firewall to prevent users on its network from accessing adult material. Similarly, in some nations, the government runs a firewall that can prevent people inside that nation-state from accessing certain parts of the Internet.

Advantages of a Firewall

•  A Firewall prevents hackers and remote access.
• It protects data.
• Also, it ensures better privacy and security.
• It protects from Trojans.
• A network-based Firewall, like a router, can protect multiple systems, while an OS-based Firewall can protect individual systems.

Disadvantages of a Firewall

• Cost: Firewall installation can be costly, depending on the sophistication required.
• Performance: This is affected as each packet has to be verified for authenticity before it is allowed into the network.
• Virus and Malware: A firewall has a few limitations, one of which is its inability to prevent virus and malware attacks, for which separate applications would be required, at the individual system level.
• A network-level Firewall might give employees a false sense of security and cause them to slack on securing individual systems. Companies need to make all employees understand the concept of a Firewall and its importance for information security and their responsibilities.
• Firewall maintenance and upgradation require an extra workforce and resources.

Conclusion

So this issue, like what a firewall is and how it works, is clear. Creating a Firewall for a home computer is easy to implement. It is easy to learn how to use it. Therefore, a learner should be able to explain a firewall and elaborate on its meaning.

FAQ