{"id":397,"date":"2024-09-22T14:16:17","date_gmt":"2024-09-22T11:16:17","guid":{"rendered":"https:\/\/avenacloud.com\/blog\/what-is-dns-and-how-does-it-work\/"},"modified":"2026-03-13T20:04:05","modified_gmt":"2026-03-13T18:04:05","slug":"what-is-dns-and-how-does-it-work","status":"publish","type":"post","link":"https:\/\/avenacloud.com\/blog\/what-is-dns-and-how-does-it-work\/","title":{"rendered":"What is DNS and How Does It Work?"},"content":{"rendered":"<p dir=\"auto\">The <strong>Domain Name System (DNS)<\/strong> remains the unsung hero of the internet. Every time you type a website like &#8220;google.com&#8221; or open an app that connects online, DNS quietly translates that human-friendly name into a machine-readable <a href=\"https:\/\/avenacloud.com\/ip\/\"><strong>IP address<\/strong><\/a> (like 142.250.190.46 for IPv4 or 2607:f8b0:4004:808::200e for IPv6). Without DNS, you&#8217;d have to memorize long strings of numbers for every site and service\u2014impossible for billions of daily connections.<\/p>\n<p dir=\"auto\">Think of DNS as the <strong>internet&#8217;s phonebook<\/strong> or <strong>smart contact list<\/strong> on steroids: distributed, hierarchical, lightning-fast, and constantly evolving, with privacy features like DNS over HTTPS (DoH) and DNS over TLS (DoT) now standard in browsers and OSes.<\/p>\n<p dir=\"auto\">This long, up-to-date guide explains everything: what DNS really is, its architecture, the step-by-step resolution magic, caching, record types, modern security\/privacy enhancements, and common real-world scenarios.<\/p>\n<div aria-label=\"\u0985\u09a8\u09c1\u09b8\u09a8\u09cd\u09a7\u09be\u09a8\u09c7\u09b0 \u099c\u09a8\u09cd\u09af \u099a\u09bf\u09a4\u09cd\u09b0\u09b8\u09ae\u09c2\u09b9: Grouped images\" data-testid=\"image-viewer\">\n<div><\/div>\n<div>\n<div><img decoding=\"async\" src=\"https:\/\/miro.medium.com\/1*-kCFoSB3-pMwajK6LTJY6Q.jpeg\" alt=\"The DNS Lookup Journey. \u2026Or one answer to the famous \u201cwhat\u2026 | by Alex Xiaoli Shen | Medium\" title=\"\"><\/div>\n<\/div>\n<\/div>\n<h3 dir=\"auto\">1. What Exactly Is DNS?<\/h3>\n<p dir=\"auto\"><strong>DNS<\/strong> stands for <strong>Domain Name System<\/strong>. Defined in RFC 1034\/1035 (1987) but massively updated over decades, it&#8217;s a decentralized, hierarchical naming system for devices and services connected to IP networks.<\/p>\n<ul dir=\"auto\">\n<li><strong>Humans<\/strong> remember and type www.example.com.<\/li>\n<li><strong>Computers<\/strong> need 192.0.2.1 (or IPv6 equivalent)<\/li>\n<\/ul>\n<p dir=\"auto\">DNS bridges that gap. It&#8217;s not just for websites\u2014email (MX records), VoIP, VPNs, IoT devices, CDNs, and cloud services all rely on DNS.<\/p>\n<p dir=\"auto\">Key facts in 2026:<\/p>\n<ul dir=\"auto\">\n<li>Handles <strong>trillions<\/strong> of queries daily<\/li>\n<li>Uses <strong>UDP port 53<\/strong> primarily (fast), with <strong>TCP 53<\/strong> for large responses<\/li>\n<li>Modern transport: DoH (port 443 HTTPS) and DoT (port 853 TLS) encrypt queries to prevent snooping<\/li>\n<\/ul>\n<h3 dir=\"auto\">2. The DNS Hierarchy\u2014How Domains Are Organized<\/h3>\n<p dir=\"auto\">DNS is structured like an upside-down tree:<\/p>\n<ul dir=\"auto\">\n<li><strong>Root zone<\/strong> (.)\u2014Managed by 13 logical root server clusters (A\u2013M), anycasted worldwide for redundancy.<\/li>\n<li><strong>Top-Level Domains (TLDs)<\/strong>\u2014.com, .org, .net, .io, .app, country codes (.uk, .de), and new gTLDs (.xyz, .online).<\/li>\n<li><strong>Second-level domains<\/strong>\u2014example.com, google.com<\/li>\n<li>www.example.com, mail.example.com, api.dev.example.com<\/li>\n<\/ul>\n<div aria-label=\"\u0985\u09a8\u09c1\u09b8\u09a8\u09cd\u09a7\u09be\u09a8\u09c7\u09b0 \u099c\u09a8\u09cd\u09af \u099a\u09bf\u09a4\u09cd\u09b0\u09b8\u09ae\u09c2\u09b9: Grouped images\" data-testid=\"image-viewer\">\n<div>\n<div><img decoding=\"async\" src=\"https:\/\/substackcdn.com\/image\/fetch\/$s_!_iP7!,f_auto,q_auto:good,fl_progressive:steep\/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8a5ed500-6b67-4b36-b6fc-fe04d8b02914_2876x1697.png\" alt=\"SDC#24 - How DNS Works? - by Saurabh Dashora\" title=\"\"><\/div>\n<\/div>\n<\/div>\n<p dir=\"auto\">This delegation system lets domain owners control their portion while the global system stays scalable.<\/p>\n<h3 dir=\"auto\">3. Key Players in DNS Resolution<\/h3>\n<div>\n<div>\n<div dir=\"auto\">\n<table dir=\"auto\">\n<thead>\n<tr>\n<th data-col-size=\"sm\">Role<\/th>\n<th data-col-size=\"lg\">Description<\/th>\n<th data-col-size=\"lg\">Examples in 2026<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td data-col-size=\"sm\"><strong>Stub Resolver<\/strong><\/td>\n<td data-col-size=\"lg\">Your device\/browser\/OS client that starts the query<\/td>\n<td data-col-size=\"lg\">Chrome, Firefox, iOS\/macOS\/Android<\/td>\n<\/tr>\n<tr>\n<td data-col-size=\"sm\"><strong>Recursive Resolver<\/strong><\/td>\n<td data-col-size=\"lg\">Does the heavy lifting\u2014queries other servers until it gets the answer<\/td>\n<td data-col-size=\"lg\">1.1.1.1 (Cloudflare), 8.8.8.8 (Google), Quad9, ISP-provided<\/td>\n<\/tr>\n<tr>\n<td data-col-size=\"sm\"><strong>Root Nameservers<\/strong><\/td>\n<td data-col-size=\"lg\">Point to TLD servers<\/td>\n<td data-col-size=\"lg\">a.root-servers.net \u2192 m.root-servers.net (13 clusters)<\/td>\n<\/tr>\n<tr>\n<td data-col-size=\"sm\"><strong>TLD Nameservers<\/strong><\/td>\n<td data-col-size=\"lg\">Know authoritative servers for domains under that TLD<\/td>\n<td data-col-size=\"lg\">a.gtld-servers.net for .com<\/td>\n<\/tr>\n<tr>\n<td data-col-size=\"sm\"><strong>Authoritative Nameservers<\/strong><\/td>\n<td data-col-size=\"lg\">Hold the actual records for a specific domain<\/td>\n<td data-col-size=\"lg\">ns1.example.com, Cloudflare\/Google DNS, AWS Route 53<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<div>\n<div><\/div>\n<\/div>\n<div><\/div>\n<\/div>\n<div aria-label=\"Difference Between Recursive DNS &amp; Authoritative DNS - Cisco Umbrella\" data-testid=\"image-viewer\">\n<div>\n<div>\n<div><img decoding=\"async\" src=\"https:\/\/cdn.umbrella.marketops.umbrella.com\/wp-content\/uploads\/2020\/06\/16092413\/What-is-the-difference-between-Authoritative-and-Recursive-DNS-Nameservers_Cisco-Umbrella-blog_DNS-server-diagram.jpg\" alt=\"Difference Between Recursive DNS &amp; Authoritative DNS - Cisco Umbrella\" title=\"\"><\/div>\n<\/div>\n<\/div>\n<\/div>\n<h2 dir=\"auto\">How DNS Resolution Works\u2014Step-by-Step (The Magic)<\/h2>\n<p dir=\"auto\">When you type <strong>example.com<\/strong> and hit Enter:<\/p>\n<ol dir=\"auto\">\n<li><strong>Browser\/OS cache check<\/strong>\u2014if recently visited, instant hit.<\/li>\n<li><strong>The local resolver (stub)<\/strong> sends a query to the configured <strong>recursive resolver<\/strong> (e.g., 1.1.1.1).<\/li>\n<li>The recursive resolver checks <strong>its cache<\/strong>.<\/li>\n<li>If miss \u2192 Queries a <strong>root server<\/strong>: &#8220;Who handles .com?&#8221;<\/li>\n<li>Root replies, &#8220;Ask these TLD servers for .com.&#8221;<\/li>\n<li>Recursive queries TLD server: &#8220;Who handles example.com?&#8221;<\/li>\n<li>TLD replies, &#8220;The authoritative servers are ns1.exampledns.com, etc.&#8221;<\/li>\n<li>Recursive queries authoritative server: &#8220;What&#8217;s the A\/AAAA record for example.com?&#8221;<\/li>\n<li>Authoritative replies: &#8220;example.com \u2192 93.184.216.34&#8221;<\/li>\n<li>Recursive caches &amp; returns IP to your device.<\/li>\n<li>The browser connects via HTTP\/HTTPS.<\/li>\n<\/ol>\n<p dir=\"auto\">This usually takes <strong>&lt;50 ms<\/strong> thanks to caching and anycast routing.<\/p>\n<div aria-label=\"\u0985\u09a8\u09c1\u09b8\u09a8\u09cd\u09a7\u09be\u09a8\u09c7\u09b0 \u099c\u09a8\u09cd\u09af \u099a\u09bf\u09a4\u09cd\u09b0\u09b8\u09ae\u09c2\u09b9: Grouped images\" data-testid=\"image-viewer\">\n<div>\n<div><\/div>\n<\/div>\n<div>\n<div><img decoding=\"async\" src=\"https:\/\/miro.medium.com\/1*goSb1oow5UBNF3KkzvOX8A.png\" alt=\"Explaining DNS Resolution. DNS resolution, or Domain Name System\u2026 | by Soulaimane YAHYA | Medium\" title=\"\"><\/div>\n<\/div>\n<\/div>\n<p dir=\"auto\"><strong>Recursive vs Iterative Queries<\/strong><\/p>\n<ul dir=\"auto\">\n<li>Recursive: Client asks the resolver to &#8220;do all the work for me.&#8221;<\/li>\n<li>Iterative: Resolver asks others &#8220;give me the next step&#8221; (most root\/TLD use iterative)<\/li>\n<\/ul>\n<h3 dir=\"auto\">DNS Caching\u2014Why It&#8217;s So Fast<\/h3>\n<p dir=\"auto\">Caching happens at every level:<\/p>\n<ul dir=\"auto\">\n<li>Browser cache (Chrome: chrome:\/\/net-internals\/#dns)<\/li>\n<li>OS cache (\/etc\/hosts overrides, systemd-resolved)<\/li>\n<li>Local router cache<\/li>\n<li>Recursive resolver cache (ISP\/public DNS)<\/li>\n<li>Authoritative doesn&#8217;t cache queries<\/li>\n<\/ul>\n<p dir=\"auto\"><strong>TTL<\/strong> (Time To Live) in seconds controls how long records stay cached (e.g., 300s = 5 minutes)<\/p>\n<h3 dir=\"auto\">Common DNS Record Types (2026 Essentials)<\/h3>\n<ul dir=\"auto\">\n<li><strong>A<\/strong>\u2014IPv4 address<\/li>\n<li><strong>AAAA<\/strong>\u2014IPv6 address<\/li>\n<li><strong>CNAME<\/strong>\u2014Alias (points to another domain)<\/li>\n<li><strong>MX<\/strong>\u2014Mail servers<\/li>\n<li><strong>TXT<\/strong>\u2014Verification, SPF, DKIM, DMARC<\/li>\n<li><strong>NS<\/strong>\u2014Nameservers<\/li>\n<li><strong>SOA<\/strong>\u2014Start of Authority (admin info)<\/li>\n<li><strong>CAA<\/strong>\u2014Certificate Authority restrictions<\/li>\n<li><strong>SVCB\/HTTPS<\/strong>\u2014Newer records for service binding &amp; Encrypted Client Hello, hints.<\/li>\n<\/ul>\n<h3 dir=\"auto\">Modern DNS in 2026: Privacy, Security &amp; Performance<\/h3>\n<ul dir=\"auto\">\n<li><strong>DNS over HTTPS (DoH)<\/strong>\u2014Queries inside HTTPS (port 443) \u2192 Mozilla, Chrome, <a href=\"https:\/\/avenacloud.com\/blog\/how-to-install-pip-on-windows\/\">Windows<\/a> 11, Android default options<\/li>\n<li><strong>DNS over TLS (DoT)<\/strong>\u2014Encrypted on dedicated port 853<\/li>\n<li><strong>DNSSEC<\/strong>\u2014Cryptographic signatures prevent spoofing (more widely deployed)<\/li>\n<li><strong>QNAME minimization<\/strong>\u2014reduces data leaked to upstream servers<\/li>\n<li><strong>Oblivious DoH<\/strong> &amp; emerging protocols hide even more metadata<\/li>\n<\/ul>\n<p dir=\"auto\">Threats: DNS hijacking, cache poisoning, and DDoS on resolvers\u2014mitigated by signed records and encrypted transports.<\/p>\n<h2 dir=\"auto\">Real-World Examples &amp; Troubleshooting<\/h2>\n<ul dir=\"auto\">\n<li><strong>Why does my site load slowly?<\/strong> \u2192 Low TTL after update, or resolver far away (use closer public DNS).<\/li>\n<li><strong>DNS_PROBE_FINISHED_NXDOMAIN<\/strong> \u2192 Typo, expired domain, or propagation delay.<\/li>\n<li><strong>Flush DNS<\/strong> \u2192 ipconfig \/flushdns (<a href=\"https:\/\/avenacloud.com\/blog\/how-to-install-pip-on-windows\/\">Windows<\/a>), sudo systemd-resolve &#8211;flush-caches (Linux).<\/li>\n<\/ul>\n<p dir=\"auto\">Test with dig example.com @1.1.1.1 or online tools.<\/p>\n<h3 dir=\"auto\">Conclusion<\/h3>\n<p dir=\"auto\">DNS is deceptively simple yet incredibly powerful\u2014the backbone that makes the modern internet usable. In 2026, with encrypted transports everywhere and faster anycast networks, it&#8217;s more private and resilient than ever.<\/p>\n<p dir=\"auto\">Next time you browse, remember that split-second load is thanks to a global, distributed army of DNS servers working together seamlessly.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The Domain Name System (DNS) remains the unsung hero of the internet. Every time you type a website like &#8220;google.com&#8221; or open an app that connects online, DNS quietly translates that human-friendly name into a machine-readable IP address (like 142.250.190.46&#8230; <\/p>\n","protected":false},"author":1,"featured_media":398,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[895,1234,1233,400,1235,614,1208,1237,1236,401],"class_list":["post-397","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-dns-management","tag-cybersecurity","tag-digital-systems","tag-dns","tag-domain-names","tag-internet-protocols","tag-it-infrastructure","tag-networking","tag-online-resources","tag-tech-education","tag-web-hosting"],"_links":{"self":[{"href":"https:\/\/avenacloud.com\/blog\/wp-json\/wp\/v2\/posts\/397","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/avenacloud.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/avenacloud.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/avenacloud.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/avenacloud.com\/blog\/wp-json\/wp\/v2\/comments?post=397"}],"version-history":[{"count":5,"href":"https:\/\/avenacloud.com\/blog\/wp-json\/wp\/v2\/posts\/397\/revisions"}],"predecessor-version":[{"id":6534,"href":"https:\/\/avenacloud.com\/blog\/wp-json\/wp\/v2\/posts\/397\/revisions\/6534"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/avenacloud.com\/blog\/wp-json\/wp\/v2\/media\/398"}],"wp:attachment":[{"href":"https:\/\/avenacloud.com\/blog\/wp-json\/wp\/v2\/media?parent=397"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/avenacloud.com\/blog\/wp-json\/wp\/v2\/categories?post=397"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/avenacloud.com\/blog\/wp-json\/wp\/v2\/tags?post=397"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}