How To Make Use Of DNS Filtering On Linux

Harmful websites and malicious content on the internet are becoming a more significant threat to company networks every day. When you have a large team of employees working remotely, you don’t have much control over what they access while also being connected to the corporate network. In order to ensure data security in a company, DNS Filtering looks to be an excellent cybersecurity practice. 

Domain Name System (DNS) Filtering is the practice of filtering bad and inappropriate websites in order to block users from accessing them in a private network. When you consider how much bad contents are on the internet, the thought of blocking them via their domains is an incredibly effective way to put an end to some of the risks posed to your network. 

What Is DNS Filtering? 

First of all, let’s start by defining the Domain Name System (DNS). DNS is the way the internet defines websites with their domain names. All domain names are connected to an IP address, but as you can imagine, remembering all IP addresses of websites we use every day would not be very sustainable. Instead, we use their domain names which are usually the name of the website. 

As a cybersecurity practice, DNS Filtering basically ensures that the IT security team of a company can put certain domain names on a blocklist, and those websites or content become unavailable to the users of the said network. This would be a great advantage when you think about how many websites are out there looking for an opening to steal and sell valuable data. 

How Does DNS Filtering Work? 

Domain names are almost instantaneous with the IP address being processed when someone tries to open up a webpage. This means that no one can visit a website without DNS being processed. The good thing is that this process makes it easier for a security team to acknowledge the threats beforehand and just block that domain name for good. 

When you are connected to a private network (this would most likely be a company network), all DNS inquiries have to go through a DNS resolver. This would make sure that your DNS inquiry is resolved and that you are now cleared to connect to the website you are trying to. 

If the said private network is using a DNS Filtering system, there would be a blocklist (or an allowlist depending on the choices) which acts as a barrier between the private network and the malicious or approved websites. DNS Filtering investigates the DNS inquiry, decides whether it is allowed or blocked, and acts accordingly. 

Let’s say that an employee is looking to visit a website that is known to be malicious by an IT security team. The employee might not be trained in cybersecurity so they might not know they are putting corporate data at risk. But since DNS Filtering will block that website before the domain name is processed, the employee will not be able to actually open up the webpage and the corporate data will not be compromised. 

This is perhaps the easiest way to protect your network against phishing attacks and malicious or inappropriate content. One thing to remember is that DNS Filtering is not usually an isolated security practice, but a part of a greater cybersecurity system. One of the easier ways to implement this great future is utilizing a Virtual Private Gateway from a reliable vendor. 

Benefits Of DNS Filtering On Linux

Linux is usually preferred over Windows in networking due to being a resourceful, affordable, and easy-to-customize system. If you want to implement a DNS Filtering solution in your Linux network, you are making a sound choice to protect the valuable data you store. Let’s see how to make use of DNS Filtering on Linux. 

1-) Blocking Phishing Websites

Phishing is a huge problem for any private network, espacially for companies with remote workers. There is always the risk of employees being scammed by phishing websites. If you are running a Linux system, using a DNS Filtering system would help greatly in terms of blocking phishing platforms and websites. According to APWG, phishing is responsible for 6.5% of all attacks.

2-) Enforcing Allowed Internet Usage Policy

If you don’t have a robust system in place, enforcing might not be as easy as implementing them to your cybersecurity guide. But when you utilize DNS Filtering with a reliable provider, you can create blocklists or allowlists to ensure everyone on the network is on the same page when it comes to allowed internet usage. 

3-) Prevent Ransomware And Cryptojacking Attacks

Malicious websites and content is not only dangerous for the phishing risk, there is always a change to get ransomeware or be a victim of cryptojacking attacks due to bad content on the internet. Using a DNS Filtering ensures that all the websites accessible from your network are approved and those that are not is beyond the reach of your users.

4-) Increasing Productivity Among Employees

A website does not have to pose cybersecurity risks to your company in order to use a DNS Filtering system on Linux. Some verified and reliable website are simply bad for productivity, they are not to be accessed from a company network used for work. Luckily, you can include these to your blocklist and employees will not be able to use these productivity draining platforms. 

5-) Improve Granular Security

Security is not always about the bigger picture, sometimes you need to ensure granular security to be safe from cyberthreats. A great way to improve granular security on your network is picking certain websites and putting them on your blocklist thanks to DNS Filtering. 


Long story short, DNS Filtering is a great tool that will improve the overall security on your private network by ensuring only allowed websites are accessible to all users. This will guarantee that you are safe from the phishing attacks, ransomware, and other cyberthreats that are common on malicious websites. Don’t forget that your users are the first line of defense on the network, and they need to be protected from everyday threats.

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