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What is a firewall?

A firewall is a network security system that monitors and controls network traffic based on an organisations security policies. They allow access to non-threatening traffic and deny access to any potentially dangerous traffic. Essentially, firewalls are a barrier that sits between internal and external networks and filters out unauthorised traffic.

Firewalls are a crucial security measure that can be used in both personal and corporate environments, in the form of software or hardware. Typically in workplaces, firewall software is installed on employee’s computers along with firewall hardware being utilised across the entire network – creating a double barrier for data requests. 

How does a firewall work?

Firewalls work by establishing a boundary between external networks and the network it’s protecting. They are applied at the perimeter of a network connection and analyse every packet that enters and leaves the network. 

Packets are pieces of data, or ‘units of communication’, that are formatted for internet transfer. Each packet contains its unique data, along with details about the data such as where it came from. 

As the firewall inspects the packets, it uses the information and checks it against the preconfigured rules to help detect malicious or threatening activity. The firewall will then allow or deny access to the network. 

The rules given to a firewall can be based on several elements including the source, destination and content itself. The rules can also be changed by an individual or company at a given time to control how ‘dangerous activity’ is defined.

It’s important to note that packets can be represented differently at different levels of the network as they are reformatted during transmission. Different types of firewalls will be able to read packets at different levels, so it’s important to choose the right firewall for your data protection.

Types of different firewalls 

There are different types of firewalls which can examine network traffic in varying levels of context. They can also be utilised in the form of software or hardware. 

Software firewalls are typically programs that are installed onto a computer, whereas hardware firewalls are a physical solution stored between a network and gateway. 

Packet-filtering firewall 

Packet-filtering firewalls are the most basic type of firewall. They work by analysing small packets in terms of their source, destination address, protocol and port number. The packet is then distributed according to the rules set by the organisation. They inspect each packet individually and do not have context as to whether there is a relation to existing traffic. 

Proxy firewalls 

Proxy firewalls act as the middleman between internal networks and outside web servers. This type of firewall protects the network whilst filtering messages at the application layer, meaning external network connections cannot directly contact the protected network. 

Stateful firewalls 

Stateful firewalls keep track of established connections within a network and examine all incoming network traffic to determine whether new packets have a connection with existing ones. This is a more dynamic firewall that stores the state of connections which assists with detecting new and threatening packets.

Network address translation firewalls 

Network address translation firewalls provide a deep-level packet inspection through the translation of external and internal IP addresses. This firewall works by directing inbound traffic to a public IP address, which is then translated to an internal IP address. The firewall will then only provide access to devices that the private network has solicited. 

Next-generation firewalls 

Next-generation firewalls are an advanced type of firewall which uses a multilayered approach to provide additional features, such as application awareness and integrated intrusion prevention systems.

How important is it to use a firewall?

Firewalls have been a massive influence on modern cybersecurity techniques after their initial introduction back in the 1980s. They were one of the first security methods designed for the internet and have been refined over the years to handle more complex issues. 

Today, firewalls are considered an essential security practice, with some smart devices having them pre-installed such as Apple Mac and Windows. Even if you are savvy when it comes to cybersecurity defence and take regular protective measures, cybersecurity threats are constantly evolving and becoming more difficult to defend against. This is why it’s important to have further security defence within your network such as a firewall. 

What are the benefits of using a firewall?

There are many benefits of using a firewall, whether it’s at home or in the office, and it is a simple way to boost your cybersecurity. Some of the top benefits are as follows:

  • Monitoring your network traffic will help to filter out any unauthorised traffic which could compromise your system’s security. It will ensure all of your personal data is safe and secure.
  • Firewalls will help to prevent cyber attacks, including malware and trojans. These cyber threats can have serious impacts that can cause practical and financial damage to an organisation.
  • With network traffic being closely filtered, firewalls help to prevent hackers from accessing your network. 
  • In general, having a firewall promotes privacy so if your business deals with confidential information, you can feel more confident with it being safely stored. 

Tips on using a firewall 

To ensure you’re getting the best security from your firewall, there are a few things to keep in mind:

  • Ensure your firewall is always turned on. In some cases, you might turn it off to access a different network, but as soon as you turn it off, your device will be vulnerable. Instead of turning your firewall off, you can update the rules so that it allows you to access additional networks.
  • Remember to deny unknown access requests. If you’re asked to allow or deny a new user to your network, always make sure you deny it for maximum security. If you’re unsure about the request, you can investigate further and update the firewall rules if they have been given permission to access. 
  • Be cautious and install additional security measures. Firewalls are not concrete security guards and will only protect against dangerous network traffic, so you still need to have other security programs installed to prevent different viruses.
  • Get into the habit of keeping your device or firewall updated – outdated software is more likely to be at risk of security breaches. 

Network security is fundamental to any organisation. If you need more support, we offer network security services that will help keep your network safe. 

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