What is DNS Filtering? And How Can It Protect Me?
by Serena Raymond on Apr 13, 2021, 12:00:00 AM
To absolutely no one’s surprise, cybersecurity threats continue to grow in number, complexity, and damage. Malware. Botnets. DDoS attacks. Phishing. Ransomware. Trojans. Worms. These terms sound ominous because they are—any of these types of attacks can result in major monetary losses for companies. As is the case with so many things, sometimes the best defense is simple—yet powerful. Something that leverages one of the very building blocks of the world wide web: DNS filtering.
What is DNS filtering?
DNS filtering is defensive software that prevents cybersecurity threats by following simple logic: if a website has something potentially dangerous within it, DNS filtering blocks a user from visiting it in the first place. It’s a zero-trust solution that leaves nothing to chance.
How does DNS filtering work?
We’ve covered some of the basics of DNS filtering in a past blog, so if you’re looking for a more detailed history, check out this post.
As a refresher, DNS stands for Domain Name System. This system has been around, in some form or another, since the 1970s. DNS is a decentralized system that maps names to their respective IP addresses, thereby ensuring that there are no duplicate domain names and that internet users have a more user-friendly experience.
Think of DNS as the Yellow Pages for the internet: if you need to reach out to John Jones, for example, you look him up in the phone book using his name, but it’s his phone number that actually connects you with him. In the same way, if you want to visit the New York Times website, you look up the domain name “nytimes.com” but it’s the string of numbers (the IP address) associated with this domain name that actually connects you to the site.
If DNS is the internet’s phone book, DNS filtering is akin to blocking unwanted calls using caller ID.
What are the benefits of DNS filtering?
DNS filtering technology is more than just a method to filter web content. It’s a shield that cybersecurity professionals can leverage to bolster one’s cybersecurity efforts.
Secure your company with DNS filtering
When you enter a domain name into your browser, DNS filtering categorizes the intended web page before it loads. Categories include personal sites, entertainment, news and media, social networking, and education (to name a few). DNS filtering also categorizes content by threat if that site is associated with any known (or unknown) threats.
Cybercrime is an unfortunate risk in today’s digital climate, but with the right tools, organizations can be properly prepared. Applying DNS filtering not only blocks unwanted web content, but you can identify and restrict access to threats. These can include:
- Purposefully deceptive sites that house malware—these sites are often brand new or recently taken over by a hacker
- Malicious ad campaigns (known as “malvertising”)
- Ransomware campaigns—a type of malware that holds computers for ransom and often targets vulnerable entities such as healthcare providers
- Phishing sites, usually linked to from spam emails, text messages, or copycat sites (often called “typosquatting”)
Many organizations utilize DNS filtering in order to prevent their users from accessing content that may lead to harmful sites like the ones listed above. Not only is the web address checked against a database, but it can be scanned to see if there are any new threats since the last time this site was accessed through a DNS resolver.
Increase productivity and block inappropriate sites
In the age of working from home, employee productivity is a major concern. DNS filtering technology, such as DNSFilter, is used by companies to prevent their employees from visiting, say, Facebook or Instagram during work hours. Schools might apply DNS filtering to ensure that students aren’t using their devices to view adult content. There are immeasurable ways in which a tool like DNSFilter can be utilized in order to control web content.
But as I stated above, DNS filtering isn’t just content filtering. It’s protective DNS and an essential part of your multi-layered, zero-trust IT infrastructure.
A Zero-Trust Solution
DNS filtering protects at a level that requires no action from the user. Whereas some security threats can only be mitigated by entrusting the user with instructions and training, DNS filtering is a solution that eliminates reliance on the individual. Where there’s trust, there’s opportunity for exploitation. To trust is to be vulnerable, and in the world of cybersecurity, vulnerabilities can be dangerous—and costly. A DNS filtering system will always block users from malicious content. Botnet, cryptomining, malware, phishing, ransomware—you name it, you’re protected.
If your organization is still relying on your users to assess and interpret their own online behavior (and risks), it’s high time to tighten your cybersecurity measures. In choosing to deploy DNS filtering, you not only have greater control over which content is available to your users, but you also strengthen your overall IT security.
Ready to see how DNSFilter's DNS filtering service can improve your overall security strategy?

I Went to Black Hat 2026 and Only Saw the Expo Floor. Here's What I Learned.
Black Hat took over Mandalay Bay this week, and the official theme was impossible to miss: AI, everywhere, all at once. The keynotes covered cyber power in the age of AI, defending when offense is cheap, and vulnerability research in the agentic age. The vendor announcements were wall-to-wall AI agents, autonomous response, and identity security. TechTarget's recap sums up the show floor mood well: Attackers are getting faster and cheaper, and ...
DNSFilter Earns 22 Badges in G2's Summer 2026 Reports
The G2 Summer 2026 reports are out, and DNSFilter earned 22 badges across the Grid® and index reports. Only a small fraction of the products on G2 earn a Leader badge in any given season, and this summer you named us a Leader across the overall Grid® Report, the Mid-Market Grid®, the Small-Business Grid®, and the EMEA Regional Grid®, along with Momentum Leader for ranking in the top 25% of our category.