In computing, firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules.

What is a firewall?

A firewall is a network security device that monitors incoming and outgoing network traffic and permits or blocks data packets based on a set of security rules. Its purpose is to establish a barrier between your internal network and incoming traffic from external sources (such as the internet) in order to block malicious traffic like viruses and hackers.

A firewall can be hardware or software-based, or a combination of two.  Most home users are more familiar with software firewalls. Many operating systems such as Windows OS and Linux come with basic, built-in software-based firewalls.  Likely, a normal user uses firewall. Anti-malware and other security products may also include software firewalls. Hardware firewalls are typically used in businesses and large corporations. These are often physical devices that are placed between the router and the internet connection. Because these are external devices, they don't consume any computing resources on the devices that connect to the internet through them, but they can be challenging to manage and configure.

How does firewalls work?

As we said, firewalls in computers analyze incoming traffic based on pre-established rules and filter traffic coming from unsecured or suspicious sources to prevent attacks. Firewall protection guard traffic at a computer’s entry point, called ports, which is where information is transferred with external devices, sources address 172.18.1.1 is allowed to reach destination 172.18.2.1 over port 22.

For example, as you know that the term ‘packets’ refers to pieces of data that are formatted for internet transfer. This packet term contains the data itself, as well as information about the data such as where it came from. Firewalls can use this packet information to determine whether a given packet abides by the rule set.  If it does not, the packet will be barred from entering the guarded network.

To make it easier, here you can find the three unique formula used by firewalls to work.

Remember, rules can be based on several things such as,

• Their source
• Their destination
• Their content

These points may be represented differently at different levels of the network. A packet is reformatted numerous times as it travels through the network to notify the protocol where to deliver it. There are various types of firewalls that can read packets at various network levels.

Types of Firewalls

There are several different types of firewall services based on their structure and functionality. Here are the various firewalls that you can implement.

Before you go ahead, remember that there are software and hardware firewalls. Each format serves a different but important purpose.  For example, a hardware firewall is physical, like a broadband router stored between your network and gateway. A software firewall is internal- a program on your computer that works through port numbers and applications.

• Packet-filtering firewalls
• Proxy service firewalls
• Stateful multi-layer inspection (SMLI) firewalls
• Next-generation firewalls (NGFW)

Packet-filtering firewalls

Packet-filtering firewalls in computers are the most common type of firewall, examine packets and prohibit them from passing through if they don’t match an established security rule set. This type of firewall checks the packet’s source and destination IP addresses. If packet matches those of an “allowed” rule on the firewall, then it is trusted to enter the network.

But remember, while packet-filtering firewalls can be helpful, they also have some limitations. Because all web traffic is allowed, a packet-filtering firewall doesn’t block web-based attacks. So, you need additional protections that distinguish between friendly and malicious web traffic.

Proxy service firewalls

The proxy service is another type of firewall.  This firewall is basically a system that can help protect your network security by filtering messages at the application layer. This proxy firewall service serves as a gateway or mediator between your internal network and outside servers on the web.  This firewall protection is aka a gateway firewall; it is more secure in its use of stateful and deep packet inspection technology to analyze incoming traffic.

Stateful multi-layer inspection (SMLI) firewalls

The SMLI firewall provides standard firewall services and keeps track of established connections. It filters traffic based on state, port, and protocol, along with administrator-defined rules and context. This involved using data from prior connections and packets from the same connection. Additionally, most firewalls rely on stateful packet inspection to keep track of all internet traffic. This stateful multi-layer inspection firewall is a step above packet-filtering in its use of multi-layer monitoring. 

Next-generation firewalls (NGFW)

A next-generation firewall is considered more sophisticated than packet-filtering and stateful inspection firewalls. This is because they provide a higher level of security by inspecting a packet as its whole rather than just filtering it. This entails not only inspecting the packet header, but also the content and source of the packet.  Additionally, NGFW can block more sophisticated and evolving security threats like advanced malware.

Why Do We Need Firewalls?

If you do internet surfing whether, for your work or enjoyment, it is important to use protection and here firewall comes in.  Firewalls, especially NGFW, focus on blocking malware and application-layer attacks. Along with integrated intrusion prevention systems (IPS), this Next Generation Firewall is able to react quickly and seamlessly to detect and combat attacks across the whole network.  

Additionally, firewalls can act on previously set policies to better protect your network and can carry out a quick assessment to detect invasive or suspicious activity, such as malware, and shut it down.  If you use a firewall for security, it implies you've put up precise regulations to allow or restrict specific types of incoming and outgoing traffic, particularly those that could compromise your company's security.

Looking for best Firewall service with extra benefits?

As we read above, a firewall is an excellent option to specify or grant permission to some websites and block others. But, with this, you also need some additional protection that can make the difference between good and bad web traffic, here antivirus or anti-malware software comes in.  You can use Priil antivirus software coming with best firewall protection and a lot more extra features. This includes a behavioral analyzer, anti-phishing & spamming, heuristic analyzer, virtual keyboard, USB protection and etc. Additionally, if you think your computer is infected with a virus or malware, you can use its 3scan mode for specific scanning. This includes custom scan, quick scan, and full scan.

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Final Touch

Hey guys! This was the guide about “what is a firewall.” Firewall protection is necessary, and it’s important to know its pure benefits so that you can choose the right firewall service for you. I hope this guide would tell you everything about firewalls, if you still have any queries regarding this article, please let us know in the comment section below.  We would be glad to answer you!