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DNS, SSL & Security
Knowledge Base
Clear, in-depth articles on DNS records, email authentication, SSL/TLS, and HTTP security headers — everything you need to understand and manage your domain infrastructure.
Featured articles
HSTS Header (Strict-Transport-Security) Explained
Understand Strict-Transport-Security directives and configure HSTS safely for your domains.
FeaturedWhat Is HSTS Preload? How Browser Preloading Works
Learn how the HSTS preload list works, the requirements to be listed, and the implications.
FeaturedThe Role of SPF, DKIM, and DMARC in Email Security
See how SPF, DKIM, and DMARC work together to prevent spoofing and improve deliverability.
FeaturedWhat Is DNS? Domain Name System Explained
DNS is the internet's address book. Learn how domain names are translated into IP addresses.
FeaturedDNS Records Explained: All Record Types
A complete guide to DNS record types — A, AAAA, CNAME, MX, TXT, NS, SOA, SRV, CAA, and more.
FeaturedWhat Is DMARC?
Learn what DMARC is, how it uses SPF and DKIM to protect your domain, and what policies mean.
DNS
2410 Best DNS Providers to Use in 2025
Compare the fastest DNS providers and choose the right resolver for performance and privacy.
What Is DNS? Domain Name System Explained
DNS is the internet's address book. Learn how domain names are translated into IP addresses.
How DNS Works: Step-by-Step Explained
Follow the complete DNS resolution process step by step — from browser query to authoritative answer.
DNS Resolution Explained
Understand recursive resolvers, iterative queries, and caching in the DNS resolution process.
What Is DNS TTL?
Learn what DNS TTL (Time to Live) is, how it affects propagation, and how to choose the right value.
DNS Cache Explained
Understand how DNS caching works at the browser, OS, and resolver levels, and how TTL controls it.
Security
11HSTS Header (Strict-Transport-Security) Explained
Understand Strict-Transport-Security directives and configure HSTS safely for your domains.
What Is HSTS Preload? How Browser Preloading Works
Learn how the HSTS preload list works, the requirements to be listed, and the implications.
HTTP Security Headers Explained
A complete guide to HTTP security headers — HSTS, CSP, X-Frame-Options, X-Content-Type-Options.
What Is Content Security Policy?
Learn what Content Security Policy (CSP) is and how it prevents XSS and data injection attacks.
CSP Examples for Websites
Real-world Content Security Policy examples for static sites, WordPress, Next.js, and API servers.
X-Frame-Options Explained
Learn what X-Frame-Options does, the difference between DENY and SAMEORIGIN, and frame-ancestors.
Email Security
12The Role of SPF, DKIM, and DMARC in Email Security
See how SPF, DKIM, and DMARC work together to prevent spoofing and improve deliverability.
What Is an SPF Record?
Learn what SPF records are, how they prevent email spoofing, and how to read SPF syntax.
How SPF Works
Understand the SPF verification process step by step — from DNS lookup to pass/fail decision.
SPF Record Syntax Guide
A complete reference for SPF record syntax — mechanisms, qualifiers, modifiers, and examples.
What Is DKIM?
Learn what DKIM is, how cryptographic signatures verify email authenticity, and how to check records.
How DKIM Works
Follow the DKIM signing and verification process from message composition to inbox delivery.
SSL
7What Is an SSL Certificate?
Learn what SSL/TLS certificates are, how they encrypt web traffic, and the different types available.
How SSL Certificates Work
Understand the complete SSL/TLS certificate lifecycle — issuance, validation, handshake, and renewal.
Types of SSL Certificates
Compare DV, OV, EV, and wildcard SSL certificates — what each validates and when to use each type.
TLS vs SSL Explained
Understand the difference between TLS and SSL and why TLS 1.3 is the current standard.
HTTPS Handshake Explained
Learn how the TLS handshake establishes a secure encrypted channel — from ClientHello to session keys.
What Is a Certificate Chain?
Learn how the SSL certificate chain of trust works and how to fix incomplete chain errors.
SSH
2SSH Keys Explained: Public vs Private Keys
Understand how SSH key pairs work, the difference between public and private keys, and how RSA, ECDSA, and Ed25519 compare.
PEM vs PPK: SSH Key Formats Compared
Learn the difference between PEM (OpenSSH) and PPK (PuTTY) private key formats, when to use each, and how to convert between them.