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Understand DNS, one clear guide at a time
DNS is the system that turns a domain name into the address of a real server, routes your email, and proves who you are online. These guides explain each piece in plain language — accurate enough for engineers, clear enough for everyone else.
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DNS Fundamentals
What is DNS?
A clear, complete guide to DNS: what the Domain Name System is, the name-to-IP hierarchy, how a query resolves step by step, caching, and zones.
9 min readWHOIS vs RDAP vs DNS
WHOIS and RDAP tell you who registered a domain and when it expires; DNS tells you where it points. Here is exactly what each one answers — and what it cannot.
9 min readIPv4 vs IPv6
IPv4 and IPv6 are the two versions of internet addresses. Learn how they differ, why IPv6 exists, how they coexist, and how each maps to DNS.
9 min readTTL & propagation
How DNS TTL controls caching, what "propagation" really means, and a safe playbook for changing records so updates take minutes, not days.
9 min readDNS Record Types
DNS record types
A clear, practical guide to the DNS record types you actually use — A, AAAA, CNAME, MX, TXT, NS, SOA, PTR, SRV and CAA — with formats and examples.
11 min readA & AAAA records
A records map a name to an IPv4 address and AAAA records map it to IPv6. Learn their anatomy, how they work together, and how to check yours.
8 min readCNAME records
A CNAME record aliases one name to another canonical name. Learn how resolution follows the chain, the rules that trip people up, and how to check yours.
9 min readSOA records
What the SOA (Start of Authority) record is, its primary nameserver, admin email, serial number, and the refresh/retry/expire/minimum timers that drive DNS.
8 min readPTR & reverse DNS
What PTR records and reverse DNS (rDNS) are, how the in-addr.arpa and ip6.arpa zones work, who controls them, and why they matter for email.
9 min readSRV records
How SRV records advertise the host and port for a named service, what priority, weight, port, and target mean, and the rules that keep them valid.
9 min readEmail & Deliverability
MX records
How MX records route inbound email to the right mail servers, how priority works, and the gotchas (no CNAMEs, no IPs) that break delivery.
9 min readTXT, SPF, DKIM & DMARC
A precise guide to TXT records and the three pillars of email authentication — SPF, DKIM, and DMARC — how each works, where it lives, and how to roll it out.
11 min readDomains & Infrastructure
DNS Security
CAA records
How CAA records tell certificate authorities which CAs are allowed to issue TLS/SSL certificates for your domain — the format, a worked example, and the gotchas.
9 min readDNSSEC
How DNSSEC cryptographically signs DNS records so resolvers can verify answers are authentic and unmodified — what it protects, what it does not, and how to enable it.
11 min read