{"id":7958,"date":"2025-09-03T09:15:00","date_gmt":"2025-09-03T14:15:00","guid":{"rendered":"https:\/\/www.dnsfilter.com\/blog\/dns-filtering-how-it-works"},"modified":"2025-09-03T09:15:00","modified_gmt":"2025-09-03T14:15:00","slug":"what-is-dns-filtering-how-does-it-work-dnsfilter","status":"publish","type":"post","link":"https:\/\/ddi.mohflo.net\/index.php\/2025\/09\/03\/what-is-dns-filtering-how-does-it-work-dnsfilter\/","title":{"rendered":"What is DNS Filtering? How Does it Work? | DNSFilter"},"content":{"rendered":"<h2><span>DNS Overview: What Is It and Why Does It Matter?<\/span><\/h2>\n<p>When you type a web address (like <code><span>www.example.com<\/span><\/code>) into your browser, a Domain Name System (DNS) lookup occurs behind the scenes. This process translates the website\u2019s domain name into its corresponding IP address (e.g., <code><span>123.45.67.89<\/span><\/code>). Some people compare DNS to a phonebook or directory for the internet.<\/p>\n<p><!--more--><\/p>\n<h3>A Brief History of DNS<\/h3>\n<ul>\n<li aria-level=\"1\"><strong>ARPAnet Era:<\/strong> In the 1970s, ARPAnet used a single file called <code><span>HOSTS.TXT<\/span><\/code> to store hostnames. Updating and maintaining this single file quickly became cumbersome.<\/li>\n<li aria-level=\"1\"><strong>Emergence of DNS: <\/strong>To fix scalability issues and duplication errors (like a second \u201cfacebook.com\u201d), a hierarchical, decentralized system was introduced: the modern Domain Name System. Today, DNS servers are distributed worldwide, allowing the internet to scale to nearly 2 billion registered domains.<\/li>\n<\/ul>\n<p>Because DNS is so foundational to how the internet works, it\u2019s also a key component in network security. Enter DNS filtering\u2014a technology that applies policies to domains in real time, blocking malicious or unwanted websites before they even load.<\/p>\n<h2>What is DNS Filtering?<\/h2>\n<p>DNS filtering is like a caller ID system for the Internet that can also block spam or malicious calls. It uses threat intelligence and categorization databases to identify whether a requested domain is safe or risky.<\/p>\n<p>In short: DNS filtering checks the website\u2019s category or reputation <em>before<\/em> the user connects, blocking anything that violates the policies you set\u2014such as social media during work hours or known malicious domains.<\/p>\n<h2>Why DNS Filtering Matters in 2025<\/h2>\n<p><strong>First Line of Defense<\/strong>: DNS filtering intercepts threats at the domain level, which is often the earliest point a user interacts with an attack site.<\/p>\n<p><strong>Scalability<\/strong>: Because DNS filtering works at the DNS layer, it can be deployed across global or remote workforces with minimal hardware.<\/p>\n<p><strong>AI-Powered Categorization<\/strong>: Modern DNS filters (like<span> <\/span><a href=\"https:\/\/www.dnsfilter.com\/product\/dnsfilter\"><span>DNSFilter<\/span><\/a>) use machine learning to catch brand-new malicious domains in real time, rather than relying solely on static threat lists.<\/p>\n<h2>How Does DNS Filtering Work?<\/h2>\n<p>When a user attempts to access a domain (e.g., <code><span>socialmedia123.com<\/span><\/code>), a DNS query is sent to a DNS resolver. Here\u2019s a basic overview if you\u2019re using a DNS filtering solution:<\/p>\n<ol>\n<li aria-level=\"1\"><strong>User Request<\/strong><br \/>The user types in or clicks on a URL in their browser.<\/li>\n<li aria-level=\"1\"><strong>DNS Query<\/strong><br \/>The request is routed to your DNS filtering provider\u2019s server (instead of a standard DNS resolver).<\/li>\n<li aria-level=\"1\"><strong>Policy &amp; Threat Check<\/strong>\n<ul>\n<li aria-level=\"2\">The DNS filter checks the requested domain against its categorization database.<\/li>\n<li aria-level=\"2\">If the domain is labeled as malicious, it blocks the request.<\/li>\n<li aria-level=\"2\">If the domain falls into a policy-restricted category (e.g., social media during work hours), the request is also blocked.<\/li>\n<\/ul>\n<\/li>\n<li aria-level=\"1\"><strong>Access or Block<\/strong>\n<ul>\n<li aria-level=\"2\">Allowed: The DNS resolver returns the IP address, and the user is directed to the website.<\/li>\n<li aria-level=\"2\">Blocked: The user sees a \u201cblock page\u201d with a customizable message or company logo.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<p>All of this happens within a split second\u2014the best DNS filtering solutions shouldn\u2019t even be noticed by the end user unless they run into a blocked request.<\/p>\n<p><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" src=\"https:\/\/i0.wp.com\/ddi.mohflo.net\/wp-content\/uploads\/2025\/09\/what-is-dns-filtering-how-does-it-work-dnsfilter.png?resize=550%2C269&#038;ssl=1\" alt=\"Example of a Block Page\" loading=\"lazy\" width=\"550\" height=\"269\" srcset=\"https:\/\/ddi.mohflo.net\/wp-content\/uploads\/2025\/09\/what-is-dns-filtering-how-does-it-work-dnsfilter-1.png 275w, https:\/\/ddi.mohflo.net\/wp-content\/uploads\/2025\/09\/what-is-dns-filtering-how-does-it-work-dnsfilter.png 550w, https:\/\/ddi.mohflo.net\/wp-content\/uploads\/2025\/09\/what-is-dns-filtering-how-does-it-work-dnsfilter.png 825w, https:\/\/ddi.mohflo.net\/wp-content\/uploads\/2025\/09\/what-is-dns-filtering-how-does-it-work-dnsfilter.png 1100w, https:\/\/ddi.mohflo.net\/wp-content\/uploads\/2025\/09\/what-is-dns-filtering-how-does-it-work-dnsfilter.png 1375w, https:\/\/ddi.mohflo.net\/wp-content\/uploads\/2025\/09\/what-is-dns-filtering-how-does-it-work-dnsfilter.png 1650w\" sizes=\"auto, (max-width: 550px) 100vw, 550px\"><\/p>\n<p><em>If your organization blocks social media sites during work hours, you might see a company-branded block page stating, \u201cAccess Restricted,\u201d whenever you try to visit Facebook between 9 a.m. and 5 p.m.<\/em><\/p>\n<h2>Why Do We Need DNS Filtering?<\/h2>\n<p><span>Beyond restricting unproductive or unsavory content, DNS filtering is crucial for cybersecurity. It prevents access to malicious sites used for phishing, ransomware, or cryptojacking attacks. Here\u2019s why it matters:<\/span><\/p>\n<h3><strong><span>Rise of Cyber Threats: Quick Stats<\/span><\/strong><\/h3>\n<p><span>In 2024, DNS-based DDoS attacks have seen a significant increase and have become a prominent attack vector. <\/span><a href=\"https:\/\/blog.cloudflare.com\/ddos-threat-report-for-2024-q1\/#:~:text=DNS%2Dbased%20DDoS%20attacks%20have,%2C%20growing%20to%20approximately%2054%25.\" rel=\"noopener\" target=\"_blank\"><span>Cloudflare&#8217;s Q1 2024 DDoS threat report <\/span><\/a><span>highlighted a staggering 80% year-over-year (YoY) increase in DNS-based DDoS attacks, reaching around 54% of all network-layer attacks.<\/span><\/p>\n<p><span>A 2021 <\/span><a href=\"https:\/\/umbrella.cisco.com\/security-definitions\/what-is-dns-security#:~:text=DNS%2Dlayer%20security%20solutions%20protect,before%20they%20reach%20the%20network.\" rel=\"noopener\" target=\"_blank\"><span>IDC survey<\/span><\/a><span> found that a staggering 87% of organizations experienced DNS attacks, indicating their widespread nature.<\/span><\/p>\n<p><span>The <\/span><a href=\"https:\/\/www.verizon.com\/business\/resources\/reports\/dbir\/\" rel=\"noopener\" target=\"_blank\"><span>Verizon Data Breach Investigations Report (DBIR) <\/span><\/a><span>highlights that phishing remains a top attack vector, accounting for 36% of data breaches.<\/span><strong><span><br \/><\/span><\/strong><span> <\/span><strong><span><br \/><\/span><\/strong><span>The <\/span><a href=\"https:\/\/heimdalsecurity.com\/blog\/dns-security-risks\/#:~:text=A%202021%20IDC%20survey%20of,for%20organizations%20in%20North%20America.\" rel=\"noopener\" target=\"_blank\"><span>average cost of a DNS attack <\/span><\/a><span>was estimated at around $950,000 globally, with North American organizations facing even higher costs, averaging about $1 million per attack.&nbsp;<\/span><\/p>\n<p><span>Information-stealing <\/span><a href=\"https:\/\/llcbuddy.com\/data\/dns-security-statistics\/\" rel=\"noopener\" target=\"_blank\"><span>malware activity was encountered by 48% of organizations<\/span><\/a><span>, highlighting the significant role DNS attacks play in spreading malware.&nbsp;<\/span><\/p>\n<h3><strong><span>Volume of New Domains<\/span><\/strong><\/h3>\n<p><span>With around 200,000 new domains created every day, it\u2019s easy for attackers to set up malicious URLs faster than you can block them manually. A DNS filtering solution with AI-driven scanning can identify and block harmful domains before a user even knows they exist.<\/span><\/p>\n<h3><strong><span>Protecting Employees &amp; Guests<\/span><\/strong><\/h3>\n<p><span>Without DNS filtering, the burden falls on employees to spot suspicious websites on their own\u2014an impossible task given the sheer volume of threats. DNS filtering automates this \u201cspot check,\u201d reducing human error and improving overall security posture.<\/span><\/p>\n<h2><span>How to Use DNS Filtering in 2025<\/span><\/h2>\n<p>Implementing DNS filtering is straightforward, especially as cloud-based solutions have matured. Here\u2019s a quick guide on how to use DNS filtering effectively:<\/p>\n<div data-hs-responsive-table=\"true\">\n<table>\n<tbody readability=\"16\">\n<tr readability=\"53.5\">\n<td readability=\"11\">\n<p><strong>Choose a Trusted DNS Filtering Provider<\/strong><\/p>\n<p>Look for features like real-time AI detection, robust reporting, and easy policy management.<\/p>\n<p>Make sure the provider has global DNS servers for low-latency lookups.<\/p>\n<\/td>\n<td readability=\"12\">\n<p><strong>Configure Your Network<\/strong><\/p>\n<p>Point your network\u2019s DNS settings (router, firewall, or endpoint devices) to the filtering provider\u2019s DNS servers.<\/p>\n<p>For remote users, consider a roaming client or VPN integration so DNS requests route through your filter even offsite.<\/p>\n<\/td>\n<td readability=\"18\">\n<p><strong>Define Policies and Categories<\/strong><\/p>\n<p>Block malicious domains by default.<\/p>\n<p>Decide which content categories (social media, gambling, adult sites, etc.) to restrict.<\/p>\n<p>Create different policies for different user groups (e.g., employees, guests, children in education environments).<\/p>\n<\/td>\n<td readability=\"9\">\n<p><strong>Monitor and Report<\/strong><\/p>\n<p>Review block logs to see attempted visits to malicious or unauthorized content.<\/p>\n<p>Use analytics to spot trends, fine-tune policy exceptions, and demonstrate ROI on security tools.<\/p>\n<\/td>\n<td readability=\"8\">\n<p><strong>Educate Users<\/strong><\/p>\n<p>Let employees know why certain categories are blocked.<\/p>\n<p>Provide training on how to handle suspicious links, even when DNS filtering is in place.<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<h2>Key Takeaways &amp; Next Steps<\/h2>\n<p>DNS filtering remains one of the most effective and low-overhead security measures available, seamlessly blending with other tools to block threats at the very first checkpoint. By thinking of DNS filtering as a form of preventive care, organizations can stop breaches before they happen and reduce overall security risks.<\/p>\n<p>To get started\u2014or to refine your existing setup\u2014start your <a href=\"https:\/\/app.dnsfilter.com\/signup\" rel=\"noopener\" target=\"_blank\"><span>free trial of DNSFilter now<\/span><\/a>.<\/p>\n<p><em><br \/>Originally written by Serena Raymond in 2021. Updated for 2025 by the DNSFilter team to reflect the latest threat landscape, new statistics, and best practices.<\/em><\/p>\n<p><a href=\"https:\/\/www.dnsfilter.com\/blog\/dns-filtering-how-it-works\">Source<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>DNS Overview: What Is It and Why Does It Matter?<\/p>\n","protected":false},"author":8,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[30],"tags":[38],"class_list":["post-7958","post","type-post","status-publish","format-standard","hentry","category-dns","tag-dns"],"featured_image_urls":{"full":"","thumbnail":"","medium":"","medium_large":"","large":"","1536x1536":"","2048x2048":"","chromenews-featured":"","chromenews-large":"","chromenews-medium":""},"author_info":{"display_name":"DNSFilter","author_link":"https:\/\/ddi.mohflo.net\/index.php\/author\/dnsfilter\/"},"category_info":"<a href=\"https:\/\/ddi.mohflo.net\/index.php\/category\/dns\/\" rel=\"category tag\">DNS<\/a>","tag_info":"DNS","comment_count":"0","jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/ddi.mohflo.net\/index.php\/wp-json\/wp\/v2\/posts\/7958","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ddi.mohflo.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ddi.mohflo.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ddi.mohflo.net\/index.php\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/ddi.mohflo.net\/index.php\/wp-json\/wp\/v2\/comments?post=7958"}],"version-history":[{"count":0,"href":"https:\/\/ddi.mohflo.net\/index.php\/wp-json\/wp\/v2\/posts\/7958\/revisions"}],"wp:attachment":[{"href":"https:\/\/ddi.mohflo.net\/index.php\/wp-json\/wp\/v2\/media?parent=7958"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ddi.mohflo.net\/index.php\/wp-json\/wp\/v2\/categories?post=7958"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ddi.mohflo.net\/index.php\/wp-json\/wp\/v2\/tags?post=7958"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}