What is a Firewall?

 In the game of network security, you are either secure or you are not; there exists no middle ground.

If a computer is connected to the Internet connection, it is vulnerable to online attacks. The only difference is some computers could be more susceptible than others.

Look at this global cyber-security statistics to get a clear picture – a Veronis report highlights that cyber-criminal attack the internet every 39 seconds and 2,244 times daily on average. Data breaches had already exposed about 4.1 billion data in 2019.

All kinds of businesses, no matter what their sizes are have become a target, especially small-scale businesses. It impacts their reputation, costs them in millions, and compromises their customer data.

This information is enough to understand that a barrier must be there to protect users from threats coming online.

What is a Firewall? 

In the computing language, a firewall is a security software or hardware that can monitor and control network traffic, both incoming and outgoing. It establishes a kind of barrier between reliable internal and unknown external networks.

Therefore, a firewall, also known as a network firewall, is capable of preventing unauthorized access to/from private networks.

A network firewall is based on security rules to accept, reject, or drop specific traffic. The aim of the firewall is to allow or deny the connection or request, depending on implemented rules.

Types of Firewalls?

You can find different types of firewalls, and sometime it might be confusing. Here are some of the popular firewall types you’ll often hear.

• Network firewall

• Web application firewall

• Hardware-based

• Software-based

• Cloud-based

• Personal computer (Windows, macOS) firewall

• Mobile firewall

They are mostly categorized under two types – network-based and host-based.

Network-based vs. Host-based firewalls

Network-based firewalls

These perform on network levels and filter all the traffic coming and going across a network. They filter traffic by checking against firewall rules and protecting the network. A network firewall is usually installed at the network edge and acts as the first layer of protection to block any unwanted traffic which shouldn’t be entering the datacentres.

Host-based firewalls

They are installed on different network nodes, controlling each outgoing and incoming packet or byte. The firewall consists of an application suite installed on a server or computer.

Host-based firewalls can protect the individual host against unauthorized access and attacks.

Hardware vs. Software vs. Cloud Firewall

Hardware-based firewall

A dedicated firewall that is installed within your network and all the traffic traverse through this device. It could be an expensive implementation but often required in an organization to protect their networks.

Some of the popular hardware firewalls come from Cisco, SonicWall, Fortinet.

Software-based firewall

It is usually a virtual appliance or VM with firewall software installed. There is plenty of open-source firewall you can explore. They are customizable but offer lesser control over protection features and functions than hardware.

Cloud-based firewall

Firewalls leveraging cloud solutions are cloud firewalls, pretty self-explanatory, right?

You can also call them Firewall-as-a-Service (FaaS), and they are similar to proxy firewalls. In addition to providing a strong shield to your network, they are excellent to scale with the growth of your company.

How does a firewall work?

A firewall maintains a set of rules which are applied to both incoming and outgoing traffic. It matches the traffic against those rules, and if the rules are matched, it initiates the access.

For outgoing traffic originating from the server, the firewall lets them pass mostly (configurable). But for incoming traffic reaching from major protocols like TCP, ICMP, or UDP, the firewalls monitor them strictly.

The firewall inspects incoming traffic based on their:

• Source

• Content

• Destination

• Port

The firewall uses this data to decide whether the traffic abides by the set rules. If yes, then it permits; otherwise, the traffic gets blocked by the firewall.

Who needs a Firewall?

Everyone!

It’s a common misconception that only large firms or financial institutions must use firewalls. But the reality is different; every business must use a firewall irrespective of their size.

A report says that 60% of SMBs that have been victims of cyber-crime went out of their business within six months.

Not to mention, cyber-criminals are always on the go to evolve their techniques and finding advanced ways to target businesses.

Without using a firewall, your network and data are potentially at major risks and vulnerabilities to malicious intent. Malware can steal your credit card data, bank credentials, customer information, destroy data, bring down your network, divert hardware bandwidth, and many more.

Hence, firewalls act as absolute saviours in these scenarios. Both consumers and corporations can use firewalls.

Companies can use firewalls into their security information & event management strategy, cybersecurity devices, etc. You can also install them in your network perimeter for guarding against external security threats or inside the network for segmenting and protecting against internal threats.

You can use a personal firewall, which is a single product consisting of software or embedded firmware device. Use it to:

• Set restrictions in your in-home devices,

• While surfing the internet using a broadband connection which is always on,

• While using public Wi-Fi in an airport, park, or cafe

• If a program tries to connect with the internet, etc.

What are the benefits of Firewalls?

Installing a firewall in your network can suppress all the jitters associated with your computer’s security.

I guess you get an idea by now, but let’s explore more.

Safer network

By monitoring traffic entering the network, a firewall keeps your network safe. By employing a 2-way firewall, you can also enjoy double-duty protection as it monitors both incoming and outgoing traffic.

It keeps an eye on every packet, and on finding a hazardous packet, the firewall blocks it then and there.

Protects from Trojans 

Trojans or Trojan horses are a type of malware that is dangerous for your computer. They silently sit on your system and spy all the files present in it. What’s more, it accumulates the information and sends it to a destined web server.

But you would not have a slight hint about what’s going on your computer until it starts showing its repercussions.

No worries if you have installed a firewall on your system as it can block Trojans immediately before they can enter and damage your computer.

Stop hackers 

Hackers are always waiting for network loopholes. Once they see it, there’s no looking back. They will target those systems and carry out malicious activities like spreading the virus through a botnet, key-loggers, and so on.

Apart from this, even your neighbours whom you might not suspect could advantage from your open network connection.

A firewall is key to all these problems and provides you with a secure network free from such intrusions.

Access control

Firewalls include access policies that you can implement for certain services and hosts. The reason is attackers may exploit some hosts, and hence your network becomes vulnerable too.

So, blocking such hosts is the solution here. You can enforce access policy on these hosts or services with the help of firewalls.

Conclusion

Firewalls are the first line of defence in your network. If that line of defence is not maintained, it could cost you millions or harm your reputation. But there’s nothing to worry; if you are using a decent firewall, you can stay secure from external threats.