Learn DNS
Understand how DNS works. Learn about record types, propagation, and best practices.
DNS Basics
Understand the fundamentals of the Domain Name System.
DNS Record Types
Learn about A, MX, TXT, CNAME, NS, SOA and more.
DNS Propagation
Understand how DNS changes propagate across the internet.
Fix NXDOMAIN & SERVFAIL
Diagnose and repair the two most common DNS errors.
How Long Does Propagation Take?
Why DNS changes can take minutes or 48 hours — and how to speed it up.
What is DNS TTL?
Time To Live controls caching and propagation speed.
What is SPF?
Sender Policy Framework — prevent email spoofing with DNS.
How to Set Up DMARC
Step-by-step guide to protecting your domain with DMARC.
What is DNSSEC?
Cryptographic DNS authentication explained.
MX Records
Mail exchanger records and how email routing works.
TXT Records
TXT records for SPF, DKIM, DMARC and domain verification.
CNAME Records
Canonical name records and when to use aliases.
CAA Records
Control which certificate authorities can issue SSL certificates.
What is DKIM?
Cryptographically sign your email so receivers can trust it.
What Are Nameservers?
How authoritative and recursive nameservers work together.
DNS Glossary
Quick definitions for every DNS term you will run into.
What Is WHOIS?
Who registered a domain, and why most of the record is redacted now.
What Is an ASN?
The number that identifies a network, and how it powers internet routing.
IP Geolocation Explained
How IP-to-location lookups work, and where they get it wrong.
What Is Certificate Transparency?
Why every public TLS certificate is logged forever, and what that reveals.
DNS Blacklists Explained
How DNSBLs work, why servers get listed, and how to get delisted.
Subdomain Enumeration
How subdomains get discovered, by defenders and attackers alike.
What Is Typosquatting?
How look-alike domains are used against your brand, and how to catch them.
Reverse IP Lookup
Every other domain quietly sharing your server's IP address.
DNS over HTTPS (DoH)
How DoH hides DNS queries inside ordinary HTTPS traffic.
IPv6 Readiness Explained
What actually needs to work for a domain to be IPv6-ready.
Does DNS Speed Matter?
What determines lookup speed, and when it stops mattering at all.
Google Workspace Email Setup
The exact SPF, DKIM and DMARC records Google Workspace needs.
Microsoft 365 Email Setup
Why Microsoft 365's DKIM needs two CNAMEs instead of one TXT record.
Migrating DNS Providers Safely
The checklist and TTL trick that make cutover boring instead of risky.
Cloudflare DNS Setup Pitfalls
The one record that must never be orange-clouded, and why.
Subdomain on a Different Host
Why a subdomain can point anywhere, but the bare domain can't the same way.
How to Read Email Headers
The Received chain, Authentication-Results and what they reveal about spoofing.
How to Read DMARC Reports
What's inside the XML reports your DMARC record asks for, and what to look for.
Subdomain Takeover
How a forgotten DNS record left pointing at nothing becomes a vulnerability.
DNS Spoofing & Cache Poisoning
Why forging a DNS response is a race, and what makes that race unwinnable.
Site Down, DNS Fine: The Checklist
An elimination process that rules out one layer at a time, instead of guessing.
DNS Amplification DDoS Explained
How a small forged query becomes a flood of traffic at someone else's address.
We Tested 58 Public Resolvers
Real measurements, not a copied list: which resolvers actually answer reliably.
Why DNS Fails From Some Countries
When the problem is the network path, not the resolver — and the fix that works.
How the DNS Health Score Works
Every check and point deduction, explained honestly — including what it skips.