What is firewall and how do firewalls work ?

A firewall is a security device — computer hardware or software — that can help protect your network by filtering traffic and blocking outsiders from gaining unauthorized access to the private data on your computer.

Not only does a firewall block unwanted traffic, it can also help block malicious software from infecting your computer.

Firewalls can provide different levels of protection. They key is determining how much protection you need.

This article can help you learn what firewalls do and determine the level of protection that will help keep your computer and the data on it safe and secure.

Firewalls are part of your network security

Firewalls represent a first line of defense in home network security.

Your home network is only as secure as its least protected device. That’s where a network security system comes in.

A firewall shouldn’t be your only consideration for securing your home network. It’s important to make sure all of your internet-enabled devices — including mobile devices — have the latest operating system, web browsers, and security software.

Another consideration? Securing your wireless router. This might include changing the name of your router from the default ID and password it came with from the manufacturer, reviewing your security options, and setting up a guest network for visitors to your home.

What does a firewall do?

A firewall acts as a gatekeeper. It monitors attempts to gain access to your operating system and blocks unwanted traffic or unrecognized sources.

A firewall acts as a barrier or filter between your computer and another network such as the internet. You could think of a firewall as a traffic controller. It helps to protect your network and information by managing your network traffic, blocking unsolicited incoming network traffic, and validating access by assessing network traffic for anything malicious like hackers and malware.

Your operating system and your security software usually come with a pre-installed firewall. It’s a good idea to make sure those features are turned on. Also, make sure your security settings are configured to run updates automatically.

Best and common web application firewalls :

• Packet-filtering firewalls.
• Circuit-level gateways.
• Stateful inspection firewalls.
• Application-level gateways (a.k.a. proxy firewalls)
• Next-gen firewalls.
• Software firewalls.
• Hardware firewalls.
• Cloud firewalls.

How Do Firewalls Work? 

Cyberattacks can be incredibly devastating for businesses, not to mention costly—it’s estimated that in 2017, the cost of cybercrime was nearly $600 billion. With the number of targeted cyberattacks continuing to rise, managed services providers (MSPs) are under increased pressure to secure customer networks from threats.   

As an MSP, you know that having a firewall (or multiple firewalls, for that matter) can make a big difference in network security. Firewalls help protect networks and devices from a wide range of security risks, namely unauthorized access from outside your customers’ networks. They can also inform you of potentially threatening attempts to connect from within customer networks. 

Knowing how to properly articulate the role of firewalls for your customers is a key part of delivering service as an MSP. If you’ve ever had a customer ask “What does a firewall do?” or “How do firewalls work?” this guide can help walk you through simple ways to explain these concepts.  

Firewalls explained

Firewalls are software or hardware that work as a filtration system for the data attempting to enter your computer or network. Firewalls scan packets for malicious code or attack vectors that have already been identified as established threats. Should a data packet be flagged and determined to be a security risk, the firewall prevents it from entering the network or reaching your computer. 

There are several different ways security firewalls can monitor and regulate network traffic. These methods can include:

• Packet filtering. Packets are small amounts of data. When a firewall uses packet filtering, the packets attempting to enter the network are run against a group of filters. These filters remove the packets that match certain identified threats and allow the others through to their intended destination. 
• Proxy service. These firewalls are incredibly secure, but they come with their own drawbacks. They work more slowly than other types of firewalls and are often limited with regard to the sorts of applications they can support. Instead of serving as a filtration system that data passes through, proxy servers function as go-betweens. By essentially creating a mirror of the computer behind the firewall, they prevent direct connections between the customer device and the incoming packets, protecting your network location from potential bad actors.
• Stateful inspection. Where static filtering examines the packet headers, stateful inspection firewalls examine a variety of elements of each data packet and compare them to a database of trusted information. These elements include source and destination IP addresses, ports, and applications. Incoming data packets are required to sufficiently match the trusted information in order to be allowed through the firewall. Stateful inspection is a newer method of firewall filtering.