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What Is a Firewall?

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’ main purpose is to allow non-threatening traffic in and to keep dangerous traffic out.

History of firewall

Firewalls have existed since the late 1980s and started as packet filters, which were networks set up to examine packets, or bytes, transferred between computers. Though packet filtering firewalls are still in use today, firewalls have come a long way as technology has developed throughout 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 device, a proxy firewall serves as the gateway from one network to another for a specific application. Proxy servers can provide additional functionality such as content caching and security by preventing direct connections from outside the network. However, this also may impact throughput capabilities and the applications they can support.

Stateful inspection firewall

Now thought of as 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 until it is closed. Filtering decisions are made based on both administrator-defined rules as well as context, which refers to using information from previous connections and packets belonging to the same connection.

Unified threat management (UTM) firewall

A UTM device typically combines, in a loosely coupled way, the functions of a stateful inspection firewall with 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 such as 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

Also, These firewalls consist of all the capabilities of a traditional NGFW and also 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
• Greatly decrease the time from detection to cleanup with retrospective security that continuously monitors for suspicious activity and behavior even after initial inspection
• Ease administration and reduce complexity with unified policies that protect across the entire attack continuum

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. A virtual firewall is often a key component in software-defined networks (SDN).

What Firewalls Exactly Do?

A Firewall is a necessary part of any security architecture and takes the guesswork out of host level protections and entrusts them to your network security device. Firewalls, and 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 react to outside attacks across the whole network. They can set policies to better defend your network 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 and 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 their 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 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 offer protection to multiple systems, while an OS-based Firewall can protect individual systems.

Disadvantages of Firewall

• Cost: Installation of a Firewall 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: There are a few limitations in a Firewall like 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 bring in a false sense of security in employees and make them slacken on securing individual systems. Companies need to make all employees understand the concept of a Firewall. And the importance of a Firewall for information security and their responsibility.
• Firewall maintenance and up-gradation require extra manpower and resources.

Conclusion

So these issues like what is a Firewall and how it works or how does a Firewall works are clear. Then how to create 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 also elaborate on what do you mean by Firewall.