What is DNS filtering? Simplified

Ajay Ohri


The DNS filtering advanced from the beginning of the ARPANET framework/system when a text record was kept up mapping usernames to the numerical of PCs connected with the framework/system. As the ARPANET system developed, numerical addresses and physically keeping a text record of clients turned out to be too labour-intensive, and an automated naming system was created.

The new DNS consequently made translated usernames into numerical (IP) Internet Protocol addresses to make it simpler for computer services, users, and devices/gadgets to locate each other on the growing network. In the long run,  domain filtering turned into the world’s registry service and is currently a fundamental part of the usefulness of the Internet.

  1. What is DNS filtering?
  2. How does it work
  3. Can a DNS filter block all malicious websites?

1. What is DNS filtering?

The term Domain Name System filtering or DNS filtering is rarely utilized while talking about Internet security, yet it is one of the key systems utilized by Internet filters to keep clients from visiting sites holding ransomware and malware.

While it is simpler for Internet users to recall domain names than IP (Internet Protocol) addresses, it is significantly more proficient for Internet filters to check solicitations to visit sites by IP (Internet Protocol) address than by domain name. The genuine DNS filtering some portion of the activity happens when a browser has sent a solicitation to get to the content of a site and the site answers.

2. How does it work

DNS filtering is a method/technique of impeding admittance to specific IP addresses, webpages, and websites. The domain name system filtering is the thing that permits simply to recall domain names to be utilized as opposed to composing in exceptionally hard to recollect IP addresses. The domain name system maps IP (Internet Protocol) addresses to domain names to permit PCs to discover web resources. 

At the point when a domain name is bought from a domain registrar and that domain is facilitated/hosted, it is doled out an exclusive IP (Internet Protocol) address that permits the site to be found. At the point when you endeavor to get to a site, a domain name system inquiry will be performed.

Your DNS filtering server will arise into the IP (Internet Protocol) address of the webpage/domain, which will permit your browser/site to create a connection with the webserver where the site is facilitated/hosted. The webpage will at that point be stacked. The real cycle includes a few unique steps; however, it is finished in a small portion of a second.

3. Can a DNS filter block all malicious websites?

Lamentably, no DNS filtering arrangement will impede/block every malicious site, as to do as such, a webpage should initially be resolved to be malevolent/malicious. In case a cybercriminal sets up a fresh out of the new phishing page, there will be a deferment between the webpage being made and it is added and checked to a boycott/blacklist.

Nonetheless, a DNS-based web filtering will block most of the malicious sites. The motivation behind an online filter is to decrease risk, not destroy it completely. Since by far most of the malignant online content will be obstructed, risk can be essentially diminished and there might be a slim likelihood of a site being gotten to that infringe/violates your approaches.


Cloud-based DNS filtering is the best DNS filtering for organizations to shield their networks and their users from phishing, ransomware, malware, and online substance that could be a hindrance to productivity in the work environment. DNS filter services rush to execute requiring a basic redirection of the Domain Name Server and simple to oversee through an online administrative portal. 

The best free DNS filtering is ScoutDNS, AutoSPF, MXToolbox, CIRA DNS Firewall, Webroot DNS Protection, DNSFilter, and WebTitan Web Filter.

So, have you made up your mind to make a career in Cyber Security? Visit our Master Certificate in Cyber Security (Red Team) for further help. It is the first program in offensive technologies in India and allows learners to practice in a real-time simulated ecosystem, that will give them an edge in this competitive world.



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