A free, independent guide to the Domain Name System: history, resolution, records, DNSSEC, encrypted transports, and day-to-day operations. https://learndns.org/ 2026-11-09T15:37:42+00:00 Learn DNS https://learndns.org https://learndns.org/learn/part-1-index/ 2026-11-09T15:37:42+00:00 2026-11-09T14:50:56+00:00

How the internet learned to remember names, from ARPANET's HOSTS.TXT file to the global Domain Name System still in use.

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Before DNS existed, ARPANET relied on a single HOSTS.TXT file maintained by SRI-NIC — learn how this scaling crisis led to the Domain Name System.

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How ARPANET's early internet pioneers chose host names, the informal naming conventions that emerged, and why these ad-hoc systems couldn't scale.

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How the Stanford Research Institute's Network Information Center became the internet's first naming authority and kept HOSTS.TXT.

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How Paul Mockapetris designed the Domain Name System in 1983, solving ARPANET's HOSTS.TXT scaling crisis with a distributed, hierarchical architecture.

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RFC 882 and RFC 883, published in November 1983, were the original DNS specifications introducing hierarchical naming and distributed resolution.

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How DNS's three core design principles — distributed architecture, hierarchical namespace, and aggressive caching — solved the HOSTS.TXT scaling crisis.

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How BIND (Berkeley Internet Name Domain) became the dominant DNS server software, powering the majority of the internet's name resolution infrastructure.

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RFC 1034 and 1035, published in 1987, define the DNS architecture, naming rules, and query protocols that still govern the Domain Name System today.

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How the DNS root got from one server at USC-ISI to 13 anycast identities, who operates them, and why the letter count stuck.

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How the first top-level domains .com, .net, .org, .edu, .gov, and .mil were created in 1985, their intended purposes, and early adoption patterns.

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How one company won the contract to register domain names and became the gatekeeper of the early commercial internet's namespace.

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How NSF approval of registration fees in 1995 turned domain names from a free research service into assets people paid to hold.

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Notable early registrations, the first squatting fights, and the people who claimed valuable names before the market understood them.

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What Network Solutions controlled from 1993 to 1999, how that monopoly shaped registration, and why the industry pushed back.

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In 1998, Jon Postel redirected root DNS traffic to test IANA's authority — the controversial incident that shaped DNS governance and its political fallout.

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The Green Paper, the White Paper, and the fight over whether DNS governance would stay with the U.S. government or move.

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How ICANN was created in 1998 to govern DNS and domain name policy, its multi-stakeholder structure, and the political negotiations behind it.

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How the Shared Registration System broke Network Solutions' monopoly, enabled competitive domain registration, and shaped the modern registrar ecosystem.

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Legal and regulatory pressure on NSI, the arrival of competing registrars, and the opening of the multi-registrar market.

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A timeline from ARPANET in 1969 to today, covering the standards, institutions, and disputes that shaped the Domain Name System.

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How DNS answers a lookup: names, the resolution path, record types, caching, the root, zone transfers, and the wire format.

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Names, labels, the DNS tree, zones versus domains, delegation, and fully qualified names — the parts every later lesson builds on.

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Follow a DNS query step by step from browser cache through recursive resolvers to authoritative nameservers — understand how domain names become IP addresses.

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A comprehensive guide to DNS record types — A, AAAA, CNAME, MX, NS, TXT, SOA, SRV, CAA, PTR, DNSSEC records, and the new SVCB/HTTPS records.

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How DNS caches answers at every layer, how TTL and negative caching work, and how to change records without serving stale data.

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Understanding the two types of DNS servers — authoritative nameservers and recursive resolvers — and how they work together.

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The 13 root-server identities, who operates them, how anycast spreads them out, and how the root zone is signed and published.

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Zone file format and syntax, SOA record deep dive, AXFR and IXFR transfers, TSIG authentication, and modern zone management.

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DNS message format, wire encoding, UDP vs TCP, EDNS(0), port 53, and message compression — understanding DNS at the packet level.

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The business and operational side of domain names — how domains are named, registered, transferred, and managed across the registry-registrar system.

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SLDs, TLDs, subdomains, FQDNs, label rules, and internationalized domain names — every piece of a domain name explained.

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Generic, country code, sponsored, and new gTLDs — the taxonomy of top-level domains and the expansion that changed the namespace.

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From registration to expiry, redemption, and pending delete — every phase a domain passes through, with timing and implications.

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The three-tier system behind domain registration — how registries, ICANN-accredited registrars, and resellers work together.

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Domain ownership lookup from the legacy WHOIS protocol to its modern RDAP replacement — history, data fields, GDPR impact, and privacy services.

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Auth codes, transfer locks, the five-step transfer process, disputes, and bulk transfers — everything about moving domains between registrars.

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Why domain registration and DNS hosting are separate concerns, how to use third-party DNS with any registrar, and when each option makes sense.

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The Extensible Provisioning Protocol — how registrars communicate with registries to create, manage, transfer, and delete domain names.

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From foundational vulnerabilities to encrypted transport and protective DNS — how the internet's naming system learned to defend itself.

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The fundamental security flaws in DNS — from cache poisoning and the Kaminsky attack to amplification DDoS, tunneling, and domain name abuse.

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The cryptographic chain of trust that authenticates DNS — key types, record types, the validation process, and why adoption remains stubbornly low.

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How DNS queries got wrapped in HTTPS — the protocol, browser adoption, provider landscape, and the fierce centralization debate.

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The first standardized encrypted DNS transport — how it works, where it's deployed, and how it compares to DNS-over-HTTPS.

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The newest encrypted DNS transport — how QUIC improves on TLS-based protocols, what RFC 9250 defines, and where adoption stands today.

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When attackers bypass DNS itself: registrar compromise, BGP hijacking, route manipulation, and other attacks on internet routing.

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Using DNS as a defensive weapon — threat blocking, response policy zones, CAA records, and DNS monitoring for security operations.

Learn DNS https://learndns.org/learn/part-5-index/ 2026-11-09T15:37:42+00:00 2026-11-09T14:50:56+00:00

How DNS powers today's internet — from CDNs and load balancing to containers, edge computing, and zero-configuration networking.

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How content delivery networks use anycast, GeoDNS, and EDNS Client Subnet to steer each user toward a nearby edge server.

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Round-robin DNS, weighted answers, health-check failover, and the real limits of balancing traffic with DNS records alone.

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Internal vs external DNS views — how organizations serve different answers to different clients based on network location.

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Automatic DNS updates for changing IP addresses — from RFC 2136 protocol mechanics to consumer DDNS services and enterprise deployments.

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mDNS, DNS-SD, and zero-configuration networking — how your devices find printers, AirPlay speakers, and each other without any server.

Learn DNS https://learndns.org/learn/5-6-dns-containers-kubernetes/ 2026-11-09T15:37:42+00:00 2026-11-09T14:50:56+00:00

CoreDNS, Kubernetes service discovery, pod DNS policies, Docker's embedded DNS, and service mesh DNS with Consul and Istio.

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Programmable DNS at the edge, policy written as code, and how serverless workers change where each DNS decision is made.

Learn DNS https://learndns.org/learn/part-6-index/ 2026-11-09T15:37:42+00:00 2026-11-09T14:50:56+00:00

The business, governance, and legal side of domains — from ICANN policy and gTLD programs to domain investing, valuation, privacy, and legal disputes.

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What ICANN is and isn't, how it's structured, the policy development process, the IANA transition, and the controversies that have defined internet governance.

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How ICANN's 2012 expansion created hundreds of new top-level domains — the process, controversies, brand TLDs, and what comes next.

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How domain investing works: hand registrations, drops, auctions, parking, famous sales, and the aftermarket that trades names.

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How domain names are valued — comparable sales, heuristic scoring, AI approaches, automated tools, and why pricing domains remains more art than science.

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Why domain privacy matters, the difference between privacy and proxy registration, GDPR's seismic impact on WHOIS, and ICANN's ongoing policy battles.

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Domain dispute resolution — UDRP, URS, the ACPA, trademark law, reverse domain name hijacking, and the cases that shaped the rules.

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The geopolitical drama of ccTLDs — delegation battles, the .io controversy, Soviet .su, country TLDs gone global, and what happens when nations vanish.

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Hands-on DNS for people who ship software: publish a zone, fix mail, debug lookups, and automate the records you rely on.

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The complete practical walkthrough — from buying a domain to serving your first page, with every DNS decision explained.

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MX, SPF, DKIM, and DMARC: the DNS records that decide whether a message reaches the inbox or is rejected outright as spam.

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Master dig, nslookup, drill, dog, and online diagnostic tools — with practical debugging scenarios and output walkthroughs.

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The mistakes everyone makes — CNAME at apex, missing trailing dots, lame delegation, and more — with diagnosis and fixes.

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Manage DNS with Terraform, OctoDNS, and DNSControl so zone changes are reviewed in Git and applied the same way each time.

Learn DNS https://learndns.org/learn/7-6-api-driven-dns/ 2026-11-09T15:37:42+00:00 2026-11-09T14:50:56+00:00

Programmatic DNS control with provider APIs such as Cloudflare and Route 53, and how that differs from registration lookups.

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Automated SSL provisioning, blue-green deployments, canary releases, and zero-downtime migrations — DNS as a deployment primitive.

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Where DNS and domain naming are headed — from blockchain-based alternatives to quantum-resistant cryptography and the rise of AI agents.

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Blockchain-based alternatives to DNS — ENS, Handshake, Unstoppable Domains, Namecoin, and whether they'll ever replace the traditional domain name system.

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How autonomous agents discover and authenticate each other, and why DNS is becoming the discovery and identity layer they use.

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The last privacy gap in HTTPS — how ECH encrypts the SNI field, its deployment status, and implications for DNS, CDNs, and censorship resistance.

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The newest DNS record types defined in RFC 9460 — service binding, HTTPS records, eliminating redirects, and distributing ECH keys.

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Growth projections, the fastest-growing TLDs, domains in developing markets, AI-generated names, and the rise of programmatic domain registration.

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How quantum computers threaten DNSSEC's cryptographic foundations, post-quantum cryptography standards, and the timeline for preparing DNS infrastructure.

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