Firewall in Computer Networks

The protection of our sensitive data from unauthorised and unwanted sources is a major concern nowadays. Different technologies and gadgets can offer varied security levels and aid in protecting our personal data. A “firewall” is one such solution that keeps our computers as well as data safe and secure by preventing unauthorised access.

In this article, we will look more into firewalls in Computer Networks according to the GATE Syllabus for (Computer Science Engineering) CSE. We will read ahead to find out more about it.

Table of Contents

What are Firewalls in Computer Networks?
Firewall: Hardware or Software
Why Firewall?
Brief History of Firewall
How Does a Firewall Work?
Functions of Firewall
Limitations of Firewall
Types of Firewalls

What are Firewalls in Computer Networks?

A software programme that monitors and filters all the incoming and outgoing network traffic in accordance with a predetermined set of security rules is known as a firewall. A firewall is a special sort of network security device. Internal private networks and outside sources are separated by it (such as the public Internet).

The main objective of a firewall is to permit benign communication while blocking dangerous or undesirable data flow in order to safeguard the computer against viruses and attacks. A firewall is a cybersecurity technology that filters network traffic and aids users in preventing harmful malware from getting online through infected devices.

Firewall: Hardware or Software

The topic of whether a firewall is hardware or software is one of the most difficult to answer. As already said, a firewall can be either a computer application or network security equipment. This indicates that the firewall is available on both the hardware and software levels, albeit it is recommended to have both.

Although a firewall can be implemented as hardware or software, both formats provide the same function. A hardware firewall is a real-world component that connects to a gateway and a computer network. For instance, a router for broadband. A software firewall, on the other hand, is a straightforward application that is loaded on a computer and operates through installed software and port numbers.

In addition, cloud-based firewalls exist; they are frequently called FWaaS (firewall as a service). The ability to administer cloud-based firewalls centrally is one of their main benefits. Cloud-based firewalls are best recognised for providing perimeter protection, just like hardware firewalls do.

Why Firewall?

Malware and network-based attacks are the main things that firewalls are used to prevent. They can also aid in the defence against application-layer attacks. These firewalls serve as a barrier or a gatekeeper. They keep track of each attempt to connect our PC to a different network. Data packets cannot pass through them unless they are coming from or going to a user-specified authorised source.

Firewalls are made to be able to identify and respond to assaults occurring throughout the network fast. They can use rules set up to safeguard the network and quickly assess situations to look for any suspicious behaviour. In essence, the firewall can act as a traffic controller.

The following are some significant risks of not using a firewall:

Open Access

Without a firewall, a computer is providing open access to other networks. This indicates that it is accepting all connections, regardless of how they are made. Threats or attacks originating over the network cannot currently be detected. Without a firewall, we expose our devices to undesired people and other sources.

Lost or Comprised Data

Without a firewall, we are allowing anyone to access our gadgets. In other words, anyone may access our equipment and have full control over it, including the network. Cybercriminals in this situation have the ability to quickly destroy our data or use our personal information to their advantage.

Network Crashes

Without a firewall, anyone may access our network and stop it from functioning. It can prompt us to spend our hard-earned time and money to fix our network.

Therefore, it is crucial to employ firewalls in order to protect our network, computer, as well as data from unauthorised sources.

Brief History of Firewall

For more than 30 years, firewalls have served as the first and most trustworthy line of defence in network security. In the late 1980s, firewalls were invented for the first time. Initially, they were intended to be packet filters. These packet filters were nothing more than a set-up of computer networks. These packet filtering firewalls’ main job was to look for packets or bytes being sent between separate systems.

Although packet filtering firewalls are still used in outdated systems, firewalls have evolved due to ongoing development. Gil Shwed from Check Point Technologies unveiled the first stateful inspection firewall in 1993 as the technology was developing. FireWall-1 was its given name. In the year 2000, Netscreen developed its specialised firewall “Appliance”. Because of the faster internet, lower latency, and higher throughput at a lower cost, it quickly became popular and was adopted by businesses.

A new strategy for firewall implementation was introduced at the turn of the century in the middle of 2010. Palo Alto Networks introduced the “Next-Generation Firewalls.” The built-in features and capabilities of these firewalls include Hybrid Cloud Support, Network Threat Prevention, Application and Identity-Based Control, Scalable Performance, etc. As part of ongoing development, firewalls continue to receive additional functions. When it comes to network security, they are regarded as the first line of protection.

How Does a Firewall Work?

A firewall system uses pre-established rules to evaluate network traffic. Following that, it filters the traffic to stop any of that traffic from originating from unreliable or dubious sources. Only inbound traffic that is set to accept is permitted.

Typically, firewalls snoop on network traffic at the port that a computer uses to connect to the internet. Firewalls carry out this function by approving or rejecting particular data packets (communication units carried over a digital network) in accordance with pre-established security criteria. Only reputable IP addresses or sources are permitted to send outbound traffic.

Functions of Firewall

The firewall serves as a gatekeeper, as already mentioned. It examines each attempt made to reach our operating system and blocks traffic from unauthorised or unknown sources.

We can think of the firewall as a traffic controller since it serves as a barrier/filter between the computer system and external networks (such as the open Internet). Therefore, a firewall’s main job is to protect our network and data by managing network traffic, blocking undesired network traffic from coming in, and confirming access by scanning network traffic for harmful objects like malware and hackers.

In general, firewall support is included with most operating systems and security programmes, such as Windows OS. Therefore, it is wise to make sure such choices are enabled. Additionally, we can set up the system’s security settings to be updated automatically once they become available.

Firewalls are now so powerful, and they have a wide range of features and functions built-in, such as:

Application & Identity-Based Control
Network Threat Prevention
Scalable Performance
Hybrid Cloud Support
Control and Management of Network Traffic
Record and Report on Events
Access Validation

Limitations of Firewall

Firewalls are thought of as the first line of defence in terms of network security. But it remains to be seen if these firewalls are effective enough to protect our gadgets from online threats. The response can be “no.” When utilising the Internet, it is best to employ a firewall system. However, it’s crucial to employ additional defence mechanisms to assist in safeguarding the network and computer data. A firewall should not be the sole factor taken into consideration for defending the home network due to the constantly changing nature of cyber threats.

Firewalls are obviously important as a security solution, however, they have significant restrictions:

Because users can still access harmful websites, firewalls are susceptible to internal threats or attacks.
Firewalls are unable to stop the transmission of software or files that are tainted with viruses.
Firewalls are unable to stop password abuse.
Incorrectly configured security policies will not be protected by firewalls.
Firewalls are unable to defend against social engineering and other non-technical security concerns.
Attackers using modems cannot be stopped or stopped by firewalls from dialling into or out of the internal network.
Firewalls are unable to protect compromised systems.

It is advised to keep all Internet-capable devices updated as a result. The most recent operating systems, web browsers, programmes, and other security software are included in this, such as anti-virus. In addition, wireless router security should be a priority. Routinely changing the router’s username and password, checking the security configurations, and putting up a guest network for guests are all possible ways to protect a router.

Types of Firewalls

There are various sorts of firewalls, each with a particular design and purpose. Here is a list of some typical firewall configurations:

Packet-filtering Firewalls
Proxy Firewalls
SMLI (Stateful Multi-layer Inspection) Firewalls
UTM (Unified Threat Management) Firewalls
NGFW (Next-Generation Firewalls)
NAT (Network Address Translation) Firewalls

Keep learning and stay tuned to get the latest updates on GATE Exam along with GATE Eligibility Criteria, GATE 2023, GATE Admit Card, GATE Syllabus, GATE Previous Year Question Paper, and more.

Also Explore,