🗄️ DNS Guides & Tools

A record explained from first principles — how a hostname becomes an IPv4 address, the root-to-authoritative resolution chain, caching behavior, and why almost every other DNS record exists to support this one.

AAAA record explained from first principles — the 128-bit address it carries, why it's named the way it is, how resolution differs from an A record, and where it quietly breaks.

CNAME records explained from the ground up — what a canonical name actually is, how resolvers follow the chain, why it can't sit at your apex, and where it breaks.

TXT records explained — structure, limits, how SPF/DKIM/DMARC all quietly depend on them, and why one generic text field became load-bearing infrastructure.

A record vs CNAME isn't really a choice — it's a set of rules. Why the zone apex can't use a CNAME, how CNAME chaining adds resolution overhead, and a practical decision framework for every hostname you manage.

Step-by-step A record configuration across common DNS providers, apex vs subdomain setup, CDN and cloud DNS platform quirks, and how to verify a change actually took before considering it done.

A practical, provider-by-provider walkthrough for adding an AAAA record correctly — Cloudflare, Route 53, Google Cloud DNS, Azure, and registrar panels — plus verification steps.

How CDNs use CNAME records to route traffic through their edge network, what the chain looks like in practice, and how to verify and troubleshoot a CDN CNAME setup.

How TXT-based domain verification proves ownership without credentials, the main methods services use, and where verification workflows commonly go wrong.

How Google's TXT-based domain verification actually works across Search Console, Workspace, and Cloud, and why it fails more often than it should.

How Microsoft 365 and Azure AD domain verification works, why Microsoft offers both a TXT and an MX verification path, and which one to pick.

What dual-stack DNS actually means, how Happy Eyeballs decides which protocol wins, and the real operational discipline dual-stack requires — firewalls, monitoring, migration.

A complete map of every DNS record type that interacts with IPv6 — AAAA, PTR under ip6.arpa, HTTPS/SVCB hints, glue records, and how they fit together in a real zone.

What actually happens when a hostname has more than one A record — round-robin behavior, why DNS load balancing has no concept of server health, geo-distribution patterns, and when to use a real load balancer instead.

Proving non-existence in DNSSEC

A complete beginner's guide to DNS Security Extensions

How resolvers actually verify trust

A diagnostic guide to validation failures

Solving DNS's circular lookup problem

The 13 identities behind global name resolution

Registering in-bailiwick DNS the right way

DNS-based certificate trust, independent of the CA system

What browser and command-line errors like DNS_PROBE_FINISHED_NXDOMAIN and SERVFAIL actually mean at the A record level, which ones are real problems versus normal propagation delay, and how to fix each.

A structured way to diagnose AAAA record and IPv6 connectivity problems — from empty lookups to resolving-but-unreachable addresses to Happy-Eyeballs-masked failures.

Why the apex/root domain can't hold a CNAME, what breaks when people try anyway, and every practical workaround — ALIAS records, flattening, and redirect strategies.

A complete rulebook for CNAME restrictions — apex conflicts, coexistence rules, MX/NS interactions, provider-specific quirks, and how to work around each one correctly.

How CNAME flattening actually works under the hood, how it differs from a real CNAME and from ALIAS/ANAME records, and what to watch for across providers.

The real security implications of TXT records — SPF misconfiguration, DMARC policy gaps, stale verification strings, and information disclosure risks worth auditing for.