A firewall is a piece of security software or firmware that can prevent any unauthorized access to a particular network. Any computer that is online is susceptible to attack, but a firewall is able to restrict unauthorized access. The firewall basically inspects all incoming and outgoing traffic by utilizing a set of preconceived rules in which to identify and stop any threats. Firewalls are an essential part of any network at all. Whether that be an individual laptop or a multinational organization.

Why are Firewalls Important?

Firewalls are basically the foundation of all computer security and have been in use since the very early days of modern computing. Therefore, they have gone through a lot of upgrades and changes as the world has developed and become more and more digitized, so have firewalls become more ubiquitous and complex. They are essential pieces of software due to the fact that they have had such a huge impact on the way modern security technology is used. Pretty much all devices have a firewall installed to inspect all traffic and reduce threats. 

What are their Uses?

A firewall is an essential component in both the corporate and consumer sphere. Businesses will include them as part of the IT security strategy and are generally installed at a network perimeter to prevent any external threat. Inside the network, they can be used as a way to segment and guard the network from internal threats. Firewalls also have a log and audit function to record all events. Administrators used this data to spot patterns and improve rules around defense algorithms. Rules have to be updated often to protect businesses from cyberattacks. By using firewall data, defense patches can be developed quickly. A firewall on a personal computer will filter traffic and signal intrusions to the user. They are generally used in combination with anti-virus technology. 

How Do Firewalls work?

They work by creating a border between the network it is protecting and the external network. 

It has the ability to inspect everything coming in and leaving the network because it is placed inline across the network connection. By using a set of pre-configured parameters, it is able to spot the difference between malicious and benign packets. A packet is a piece of data formatted especially for internet transfers. Firewalls utilize this packet data and assess it against the network rules to see if it is acceptable or not. The rules the firewall follows can be based upon many things. That means different types of firewalls exist to identify different things at all sorts of network levels.

Types of Firewalls

Firewalls are determined by how they filter data or the system they are designed to protect.

Protection firewalls:

• Network-based – guard the whole network and use specific firewall hardware.
• Host-based – guards individual devices. 

Filtering firewalls:

• Packet-filtering – studies packers in isolation and doesn’t know the content.
• Stateful inspection – studies traffic to see if packers are related to each other.
• Proxy firewall – studies packets at the application layer of an open systems interconnection.
• Next-Generation Firewall – this is a multilayer firewall to integrate enterprises with intrusion prevention and application control.