What is a Firewall?

Posted on | Updated:

Do you have a firewall prepared to block all malicious traffic?

Security is at the forefront of the technology discussion. As the industry innovates and builds websites, applications, and platforms, securing the environments where these things live is increasingly essential. In the web hosting space, there are many options for securing your infrastructure.

But how do you know which ones to choose?

Of all of the options, a firewall can prove to be a simple, effective, and modest solution to data security. We want to take some time to discuss firewalls and their use to secure data. We will specifically look at:

  1. What is a Firewall
  2. The Purposes of Firewalls
  3. How Firewalls Work
  4. The Types of Firewalls
  5. Who Needs Firewalls

What is a Firewall?

A firewall is a device used in network security to monitor incoming and outgoing network traffic. It determines whether to allow or block specific traffic based on a predetermined set of security rules. Unauthorized traffic can be refused access while legitimate traffic can be allowed to reach its destination.

Functionality has changed over the years, allowing for firewall implementation in many different ways. Firewalls are set up via software or hardware means, which we will dive deeper into in this article. However, let’s first look into how they work and why they would be an essential addition to your infrastructure.

Check Mark Subscribe to the Liquid Web weekly newsletter to have more security content like this sent straight to your inbox.

What are the Purposes of Firewalls?

Firewalls are an essential addition to your infrastructure because they can help to isolate computers and servers from the internet to provide security and privacy of data. As previously mentioned, not only do they monitor traffic to and from your server, but also limit that traffic in some cases as well. The overall goal is the reduction or elimination of unwanted network connections and the free flow of the legitimate connections. Having this type of protection in place can prove to be invaluable.

For example, if we think in terms of a Denial of Service (DoS) attack, erroneous traffic floods your site and can potentially bring down the server of the targeted website. Appropriately configured firewalls serve to protect your environment from such situations. Where supported, stateful inspection techniques allow for patterns in traffic flows to be analyzed for anomalies that point to an attack being underway.

how does a firewall work

How do Firewalls Work?

Packet Filtering

Packet Filtering is a specific method for implementing a firewall to monitor network connectivity. Data packets are units of data packaged together and traveling along a given network path. The packages are analyzed and compared against the configuration rules or “access-list.” It then determines what is allowed or denied access to your environment.

Stateful Inspection

As mentioned before, stateful inspection techniques allow for patterns in traffic flows to be analyzed to determine when an attack is happening. The way this works is by the firewall noting what site or application is currently accessed. In this case, the firewall is keeping track of the “conversation list” to determine authorized data from the website or app versus any data from a hacker or other unauthorized source.

Proxy-Based Firewall

Proxy-based firewalls take stateful inspection a step further. This type of implementation prevents direct network connections between internet traffic and the server. The firewall would act as an intermediary between your server and the requests made by the end-user. Entire packets of data are examined and either blocked or allowed based on the rules set.

Now that we have discussed what a firewall is, its purpose, and how it works, let’s talk about the two implementation methods.

securing your data and infrastructure from hackers with a firewall

What are the Types of Firewalls?

There are both software-based and hardware-based firewall solutions from which to choose. Whether you need one or both of the types of firewalls depends on what you are trying to accomplish. However, if you are not using at least one of these methods to protect your environment, you may be vulnerable to nefarious network activity over the internet at large.

Software Firewalls

Software firewalls are very common because they are not required to be physically setup. They are installed locally on the device or devices you are trying to protect. You have much more granular control of the rules set up for each specific device running the software. Traffic can be analyzed down to the content and blocked based on keywords contained therein.

Since the software firewall is local, it is typically efficient with security alerts. Whether managing rules or users, administrators can refer to logs or notifications to determine what is happening on the devices. Knowing what is taking place on your systems at a moments notice works in your favor.

However, for software firewalls to work, the software would need to be installed on each device in your network. If there is no hardware firewall between the internet and your system, your infrastructure could be susceptible to attacks. It is also essential to ensure compatibility between your operating system and the software you wish to use. No matter how good the software, compatibility issues weaken the effectiveness of your security.

One small factor to note is that software firewalls can be intensive on your device’s resources. While computers and servers that have more capable hardware may not notice much of a difference, those with limited resources can slow down with some software firewalls. The more lightweight the software, the better your environment will run.

Hardware Firewalls

Having a hardware firewall ensures you have 100% control of the traffic on your network. With a single device, you can decide what traffic should or should not reach your servers. Since it is a separate device from your servers, there is no worry of performance degradation. There is no need to install or enable software firewalls as packets to be intercepted and analyzed before reaching your servers.

Hardware firewalls are also easily configured. There are usually default rules you can set and apply to all traffic. Granular control to drill rules down to distinct ports and services like SSH and RDP makes fine-tuning simple.

Another benefit to hardware firewalls is the ability to set up a Virtual Private Network connection direct to your environment. Wherever there is a stable internet connection, you can access your infrastructure. Moreover, with managed hosting providers like Liquid Web, you get help with managing and configuring your VPN tunnel.

protecting your office with a firewall

Who Needs a Firewall?

Personal and Home Networking

Those people that work or play from their home internet connection most certainly need a firewall. In most cases, some form of firewall gets used in most operating systems, home network routers, and anti-virus software. Unless there is a need beyond these standard methods, not much else is necessary. You can certainly consult with your Internet Service Provider or an Information Technology professional for assistance with home networking.

Company and Office Networking

Your office or place of business also needs security outside of the basics. Whether your infrastructure is set up in-house or hosted with a provider, ensuring data to and from your servers is legitimate and protected is a necessity. It is worthwhile to explore solutions for protecting your data and your servers.

Website and Application Server Networking

Hosting sites and applications with a managed provider still warrant a secure environment. DoS attacks, malware, and other exploits to software vulnerabilities are just a few things hackers deploy. With the proper configuration and rules in place, you can lock down your websites and applications from those that are out to get your data.

Ready to try Hardware Firewalls with Liquid Web? Learn more about how you can stay protected from malicious traffic. 


Want more news and updates like this straight to your inbox?

Keep up to date with the latest​ ​Hosting news.