What is DNS Filtering? 

DNS filtering, or Domain Name System (DNS) filtering, is a vital cybersecurity measure that involves controlling and managing access to websites by manipulating the DNS. Think of the DNS as the internet’s address book. It translates readable domains into IP addresses that computers use to locate and connect. 

In DNS filtering, specific websites or categories of content are either allowed or blocked based on predefined criteria that you can customize. This is done by implementing specialized DNS resolvers which are responsible for handling DNS queries. Let’s look at an example. 

When a user attempts to access a website, the DNS resolver checks to see if that domain has been blocked. If it is, the resolver will refuse to resolve the query, resulting in the user not being able to access the website. DNS filtering can be implemented through various methods such as: 

  • Proxy servers
  • Dedicated DNS filtering appliances 
  • Cloud-based services 
  • Software solutions installed on individual devices 

Typically, an organization will deploy DNS filtering to enhance cyber security and bot protection, protect sensitive information from any malicious activity, and enforce policies. The idea is to create a safe and controlled user experience. 

Why is DNS Filtering Important?

DNS security plays a vital role in enhancing cybersecurity and creating safer online environments. While you may be able to trust employees or young family members on the computer, you never know when something could slip through the cracks without a DNS filtering solution in place. Here are several reasons why DNS filtering is important whether it’s for business or family use. 

Protection Against Malware 

When you implement DNS filtering, it acts as a frontline defense against malware and can be a component of layered security. It does so by ensuring that users can’t access domains that have already been considered malicious. By preventing users from connecting to any malicious domain, organizations can significantly reduce the risk of malware infections that could compromise the security of their systems through a DNS filtering service. 

Not only will protecting against malware with DNS filtering give you peace of mind, but it will also save you time, energy, and money that could go into resolving a malware infection that spreads through your infrastructure. 

Phishing Prevention

How many times have you gotten a phishing scam test email at work? A phishing attack relies on deceptive websites that mimic legitimate ones. If you’ve fallen victim to one, you’re not alone. This is why it’s crucial to have a DNS filtering system in place. 

Protective DNS filtering helps identify and block access to known phishing domains, which safeguards users from falling victim to fraudulent schemes and other cyber threats. It also protects sensitive information such as login credentials and personal data. This type of domain blocking is another reason why setting up DNS web filtering is so important. 

Content Control 

Content filtering is another key element to implementing DNS filtering properly. Organizations usually have policies in place regarding acceptable internet usage. It allows them to enforce these policies by restricting access to inappropriate or non-work-related websites. By blocking websites such as social media, employees will be more focused and productive. 

Controlling content is also important for maintaining compliance with legal and regulatory requirements. This is especially crucial when working with sensitive data such as in a medical or financial office. 

Increased Productivity

This one goes hand in hand with content filtering. When you block access to websites that are distracting or unrelated to work, DNS web filtering can contribute to improved productivity in the workplace. 

This is because it helps maintain a work-centric online environment. It reduces the temptation to spend working hours on websites that waste time and are non-essential. That time then gets put towards work instead. 

Bandwidth Management 

DNS filtering is also important for managing bandwidth. This is due to how effective DNS filtering is at optimizing network performance by blocking access to bandwidth-intensive websites. This ensures that network resources are used efficiently. 

This will prevent congestion and slow-downs that could clog up the workday. With DNS filtering blocking websites using too much bandwidth, employees can no longer access non-essential sites that use excessive data. 

Protecting Sensitive Information

Protecting sensitive information is crucial in any organization. By restricting access to any malicious website that could pose security risks, DNS web filtering helps safeguard confidential data and proprietary information from unauthorized access or exposure. It’s an added line of cybersecurity defense for layered security to pair with firewalls and other tools. 

Compliance Considerations 

DNS filtering is also useful when it comes to legal and compliance considerations. Many industries are obligated to adhere to specific regulations regarding online content and data protection. 

This security measure aids in compliance efforts by restricting access to websites that may violate legal requirements, ensuring that organizations operate within legal boundaries. Before implementing DNS filtering into your current system, make sure that you’re on top of the compliance regulations that must be followed within your organization. 

Network Security

DNS filtering serves as an additional layer of network security that prevents unauthorized access to potentially harmful websites. It complements other security measures such as firewalls and antivirus software to create a comprehensive defense against a wide range of cyber threats. It works together with firewall protection and web filtering to protect your assets. 

Covering all of these bases makes DNS filtering important because it proactively addresses so many cybersecurity challenges and aids in threat prevention. Not only that, but it can help you create a more productive and focused workplace. 

Types of DNS Filtering 

With so many reasons why DNS filtering is one of the most important cybersecurity measures, several types can be implemented.

Blacklist-Based Filtering

This type of DNS filtering operates on the premise of maintaining a list of known malicious or inappropriate domains. Think of a blacklist-based filtering system like a bouncer at the club who has a list of everyone who’s not allowed in. When a user tries to go to one of the domains on the list, the DNS filter will check the list and deny them access. 


  • Proactive Defense: Blacklist-based filtering offers preemptive protection against threats that have already been recognized. These can include known malware and phishing schemes that have been reported by other organizations. 
  • Simple Implementation: This type of cybersecurity is pretty straightforward to implement. It won’t take very long and is extremely effective. 

Things to Consider 

  • Dynamic Nature: Blacklist-based filtering requires consistent updates to be effective. New threats need to be added as they are found, which is crucial in the evolving landscape of cybersecurity threats. 

Who is Blacklist-Based Filtering Best For?

This type of filtering is best for businesses that have straightforward cybersecurity requirements. For example, it may be good for small to medium-sized businesses that are only looking to block adult content and social media from their users. 

Whitelist-Based Filtering 

Operating oppositely, whitelist-based filtering focuses on permitting access only to approved websites. Going back to our club example, this would be the VIP list. So, instead of users being able to perform a trial and error to see what works, they will only have access to the list of sites that you have approved. 


  • Very Strict Control: A white-label list allows organizations to have strict control over what users can access. This eliminates any time-wasting and nonessential websites.
  • Risk Mitigation: Whitelist filtering also minimizes the potential of exposure to malicious content since they can’t access anything that isn’t on the approved list. 


  • Maintenance Overhead: Just like blacklist filtering, the whitelist requires regular updates to ensure users have access to everything they need. 

Who is Whitelist-Based Filtering Best For?

Whitelist-based DNS filtering is best for highly regulated industries such as finance or healthcare where strict control over internet access is crucial. 

Content Filtering 

Content filtering has a different perspective from the black-and-white lists. With this DNS filtering method, websites are categorized based on their content. So, instead of focusing on the reputation of the website, content is evaluated by predefined categories to see if it’s approved for access. 


  • Policy Enforcement: Facilitates organizations in enforcing content policies by restricting access to specific categories such as adult content, social media, and gambling. 
  • Adaptability: Offers flexibility to tailor the online experience in alignment with the objectives of the organization. 


  • Categorizing Challenges: The filtering system may encounter issues figuring out how to categorize certain websites. This could lead to potential threats sliding through the cracks, or necessary websites being blocked. 

Who is Content Filtering Best For?

Content filtering is best for organizations that have diverse user needs and varying internet usage policies that need very specific control. This type of filtering may be best for startups and other businesses that might be changing rapidly. That way, you can customize your content filtering based on the needs of that specific time frame. 

Before choosing a DNS filtering type, you must figure out what will work best for your organization. Weighing the advantages and disadvantages of each can help you to narrow it down. Once you’ve chosen, it’s crucial to stay up to date with the model to ensure it’s working properly to protect your data and organization. 

The Pros and Cons of DNS Filtering 

Whatever type of DNS filtering you choose, there are always going to be pros and cons. Let’s take a look at some of the top pros and cons to consider when it comes to DNS filtering. 

Pros of DNS Filtering 

Improved Security 

Since DNS filtering is considered a cybersecurity tool, you’ll benefit from increased internet security. Blocking access to malicious websites keeps your staff from being able to access them at work which eliminates the potential for them to fall for phishing scams. 

This is also beneficial at home for children who may be using the computer. Using parental controls can keep children on specific websites that you’ve approved, and away from inappropriate content. 

Faster Filtering 

The filtering process happens before any content is even downloaded, which can improve speed and security. Nothing enters your infrastructure. This will keep pages loading quickly and won’t interfere with productivity. 

It’s important to keep in mind that filtering will work best if you stay up to date on what you do and don’t want to be accessible. Doing so will ensure that no extra data is used and that filtering happens as quickly as possible. 

Simple Implementation

The implementation process for DNS filtering is simple and can be done quickly. If you’ve recently experienced a malware infection or fallen victim to a phishing scam, you can easily bring in DNS filtering to keep it from happening again as soon as you put in your configurations. 

Cons of DNS Filtering 

Bypass Potential 

One of the biggest cons to DNS filtering is that it can be easily bypassed by malicious domains. Since it queries a collection of data, the effectiveness depends on the information that the service has access to. If there’s a delay, or lists haven’t been updated, there is potential for a breach. 

Alternative DNS services and VPNs may also be used to bypass the DNS filtering that you have in place. This challenges admins to stay on top of trends and keep up to ensure that bypasses don’t happen. 

Performance Impact 

DNS filtering may introduce latency to the DNS resolution process, which can impact overall network performance. The extent of this impact depends on the chosen filtering method and efficiency. Keep this in mind when choosing a type of filtering and your business needs. 

False Positives and Negatives

There is potential for DNS filtering systems to misclassify websites, which can lead to legitimate content being blocked or allowing access to malicious content. It’s crucial to perform regular updates and fine-tune filtering policies to minimize the possibility of this happening. 


Achieving the right balance in filtering policies can be a challenge. Overblocking can restrict access to needed content, while underblocking can expose your network to potential threats. It’s important to have continuous monitoring and make adjustments when needed to avoid this. 

DNS Filtering Use Cases

The world of DNS filtering and cybersecurity can be complex. To make it simpler to understand, here are some common use cases to show you better how DNS filtering works. 

Phishing Scams

One of the most common places DNS filtering can be used is for phishing scams. There are many well-known scams out there that organizations train their staff to look out for, but they can always slip through the cracks. Having filtering in place can prevent users from falling victim to phishing attacks that work through websites pretending to be a legit site through email. 

Guest Wi-Fi Security 

Businesses that offer Wi-Fi can use DNS filtering to ensure a secure browsing experience for their guests. The filtering system prevents unauthorized access to malicious websites to protect the guests as well as the organization’s network. You’ve likely been on protected Wi-Fi before that wouldn’t let you access certain websites and had no idea. 

Healthcare Security 

Another use case is within the healthcare industry. These organizations have to comply with HIPAA and other regulations to protect sensitive information such as patient data. It helps to block access to ensure compliance with healthcare regulations. 


Educational institutions will typically implement DNS filtering to ensure a safe online environment for students and staff. This includes blocking access to inappropriate content that students and faculty alike should not have access to. 

This is likely the type of DNS you will be familiar with. It works similarly to how when you were in school they may have had parental controls in place on computers. You would only be allowed to access educational resources and games that they allowed you to play. 

Remote Work 

As remote work continues to be commonplace, DNS filtering becomes essential. Employees are working all over the globe, which calls for securing remote networks. It helps organizations extend their cybersecurity measures to employees working from various locations, protecting against online threats. 

Future Trends in DNS Filtering 

Advancements in Evasion Techniques 

As DNS filtering technologies continue to evolve, so do the malicious technologies that are trying to bypass it. Future trends may include challenges such as sophisticated evasion tactics, such as the use of encrypted DNS to hide malicious activities. This will create a type of cat-and-mouse game which will push the need for improved detection and mitigation strategies. 

Artificial Intelligence (AI)

We can’t talk about anything involving cybersecurity without talking about AI. The integration of AI into DNS filtering is a huge leap forward that will improve filtering systems. It’s going to help with analyzing data to identify patterns and adapt to evolving threats in real-time. This may decrease the amount of threats from malicious domains since they will be caught before they even make the list. AI is going to play an increasingly pivotal role in all types of cybersecurity. 

Market Growth

There’s going to be an increasing global demand for DNS security services in the coming years. Data shows that between 2023 and 2033, the demand is expected to grow at a significant compound annual growth rate (CAGR) driven by the increasing cases of cyber-criminality. 

Balancing Security and Individual Rights

With an increasing focus on individual privacy, the future of DNS filtering will likely involve a delicate balance between cybersecurity measures and protecting user privacy. As regulations continue to address privacy concerns, DNS filtering will need to adhere to strict compliance requirements to provide transparency as well as user consent. This is going to be relevant for all cybersecurity measures that involve monitoring the personal activity of users on a network, especially in the world of remote work where they may be at home using a personal computer. 

Increasing Use of Cloud-Based DNS Filtering Services 

The increasing use of cloud-based DNS filtering means organizations will have more scalability as well as flexibility. Leveraging the scalability and flexibility of cloud infrastructure, these services offer organizations the ability to adapt quickly to changing threats,  ensuring real-time updates and efficient management. 


The bottom line is that you can never be too careful when it comes to cybersecurity. Ensuring that you analyze your organization’s needs before setting up DNS filtering will get you on the right track. Always keep in mind that there are bypass risks to this type of service, so it’s crucial to stay on top of updates to keep your network secure.

Using DNS filtering along with other cybersecurity measures can improve risk mitigation and network safety. Whether you want to try a blacklist filtering system, white list, or content control, RiskRecon Threat Protection can help. Contact us today for a free demo