Articles & Guides
Useful resources for web developers and system administrators
Security
Content Security Policy (CSP) — A Complete Configuration Guide
What is Content Security Policy, how to configure the CSP header, which directives to use. Configuration examples and common mistakes.
SSL/TLS
How to Check a Website's SSL Certificate: Step-by-Step Guide
How to check a website's SSL certificate: expiration date, certificate chain, TLS protocols, vulnerabilities. Online tools and command-line methods.
Security
HSTS — What It Is and Why Your Website Needs It
What is HSTS (HTTP Strict Transport Security), how it protects against attacks, how to configure the header, and how to avoid common mistakes. A practical guide.
Tools
Batch URL Checking: Automating Website Monitoring
How to check hundreds of URLs at once: batch HTTP status code, header, and redirect verification. Tools and automation.
Networking
IP Geolocation Accuracy: How It Works and Where It Fails
How IP geolocation works, what determines location accuracy, and why VPNs and proxies introduce errors.
DNS
DNS Propagation: Why DNS Changes Don't Take Effect Instantly
Why DNS changes don't apply immediately: TTL, caching, recursive resolvers. How to speed up DNS propagation.
SSL/TLS
SSL Certificate Types: DV, OV, EV — Which One to Choose
Comparison of SSL certificate types: DV, OV, EV, Wildcard, and multi-domain. When to use Let's Encrypt vs. a paid certificate.
HTTP
Analyzing Server Response Headers: What They Reveal About a Website
A detailed guide to HTTP headers: Cache-Control, ETag, Server, CORS, and security headers. How to read and optimize response headers.
SEO
Redirect Chains: How They Affect SEO and Speed
Redirect chains slow down your site and weaken SEO. Learn the difference between 301 and 302, how to find chains, and how to fix them.
Security
API Security: Best Practices for Protection
Best practices for API security: authentication, rate limiting, CORS, HTTPS, data validation, and protection against common threats.