Aditya is an Azure DevOps and Infrastructure Virtualization Architect with experience in automation,... | See full bio
-> Published on: 27-07-2023
What is DNS Filtering?
Updated · Jul 27, 2023
Girlie is an accomplished writer with an interest in technology and literature. With years of experi... | See full bio
DNS filtering is the process of blocking access to certain websites for security reasons or to avoid distractions.
If DNS is like a phonebook of domain names and their respective IP addresses, then DNS filtering works like a caller ID blocker.
To better understand why DNS filtering is vital in cybersecurity, it is crucial to know what it is and how it works. This article will cover just that, so read on.
DNS Filtering Definition
In 2022, 83% of business owners blamed phishing for most of the cyberattacks they experienced.
A robust DNS filtering system can help avoid potential damage from phishing and other malicious attacks.
To understand what DNS filtering does, understanding how DNS resolution works is necessary:
DNS filtering happens between steps 2 and 3. As an added step, the DNS filter will check if the queried domain name matches anything in its block list.
If it does, the query will not be resolved. Instead, it will return an error message informing the user that the website is blocked.
DNS Filtering and Other Filtering Types
DNS filtering also holds the same goal as other filtering types like URL filtering and web filtering. They block a user’s access to a domain or content based on a set protocol.
However, DNS filtering is different in some ways. Check out below to know what makes it distinct.
DNS Filtering vs. Web Filtering
Web filtering is a broader concept than DNS filtering. It encompasses URL filtering, content filtering, keyword filtering, and DNS filtering itself.
These terms are often used interchangeably because their purpose is the same.
DNS Filtering vs. URL Filtering
DNS filtering blocks whole domains, while URL filtering blocks specific URLs. It means that certain web pages within a domain can still load with URL filtering.
Businesses employ URL filtering to restrict access to some web pages on their company’s website. It does the same thing as DNS filtering but on a more granular level.
Below is a summary of the differences between DNS filtering and other types:
Blocks websites based on DNS queries
Restricts website access broadly
Restricts access to specific URLs
Blocks entire domains
Covers various filtering methods
Targets specific URLs or pages
Enhances security against phishing and malware
Enforces internet policies and blocks malicious sites
Provides granular control over specific URLs
Approaches to DNS Filtering
There are three approaches to DNS filtering: manual, automatic, and managed. Take a closer look at each one below.
Manual DNS Filtering
This approach involves employing and training internal IT staff to set up a basic DNS-blocking system for certain sites.
Open-source or free DNS filtering solutions usually require extensive IT expertise. However, employing an IT staff may also cost more than the available paid DNS filtering services on the market.
Another downside of the manual approach is that it tends to be slower to adapt to evolving cyberattack tactics.
Basic web domain filtering is vulnerable to more sophisticated phishing attacks that circumvent DNS blocks.
👤 Best for: Manual DNS filtering works for small-scale businesses or individuals. This approach provides the necessary filtering but with only a few web users to monitor.
Automated DNS Filtering
Automated DNS filtering relies more on paid services for better scalability.
This approach quickly adapts to the increasing sophistication of cyberattacks. It is also easier to scale as the business grows.
The cost of automated DNS filtering varies depending on the DNS filtering software.
Managed DNS Filtering
Large-scale businesses employ this approach. It involves partnering with Managed Security Service Providers (MSSPs).
This solution is costly but offers comprehensive support for any company’s web and data security needs.
It means outsourcing all IT security duties to MSSPs—-from set up, maintenance, vulnerability testing, and emergency response to threats.
🎉 Fun Fact: Some of today’s top MSSPs are AT&T, Cipher, and IBM. Providing top-tier cybersecurity, these companies cater to clients with varying requirements in different locations.
Importance and Benefits of DNS Filtering
DNS filtering provides several benefits to businesses of all sizes. To give you a clear picture, here are the primary benefits of DNS filtering for most companies:
Providing Protection Against Phishing Attacks
Phishing or scamming employees into giving their login credentials is one of the most common forms of cyberattack.
Attackers target employees with phishing emails containing links to spoofed web pages, then ask them to sign in.
If a DNS filtering system is in place, access to these spoofed web pages will immediately be blocked, even if an employee happens to click on a suspicious link.
Blocking Malware-Hosting Sites
As an added layer of security, DNS filtering makes sure that sites with various types of malware are immediately blocked.
It is also on top of end-point device solutions like anti-malware or anti-viruses.
DNS-level protection prevents the infection of malware and viruses before they even load on any company device.
Imposing Effective Internet Policies
Businesses see the need to restrict access to sites involving alcohol, gambling, illegal file sharing, and explicit content.
Any site or content that is non-work-related and can harm the company’s software or image is blocked by DNS filtering.
🎉 Fun Fact: Do you know people spend 2.5 hours on social media? This is why companies use filtering to increase productivity and avoid distractions during work hours.
DNS filtering prevents access to certain websites at the domain level. This process is more than just blocking or allowing access to sites.
It can significantly reduce the time and money spent repairing cyberattack damage.
Is a DNS filter better than a firewall?
None is better than the other, as they have different duties. Firewalls protect networks and devices at IP and port levels, while DNS filtering examines DNS requests to prevent access to blocked websites.
Can the Internet work without DNS?
Yes and no. Yes, because DNS was not present at the onset of the Internet. No, because as the Internet grew, it became indispensable to use DNS servers to translate millions of domain names into their corresponding IP addresses.
What happens if DNS is off?
If the DNS server is unavailable, the browser will not be able to get the IP address of the target domain. You will get an error if this happens.
Your email address will not be published.
Updated · Sep 11, 2023
Updated · Sep 05, 2023