Articles & Guides

99.9% allows about 43 minutes a month — that is the easy part. What the percentage excludes, who measures it and what a service credit is actually worth.

Comparing HTTP/2 and HTTP/3 protocols: multiplexing, QUIC, head-of-line blocking, performance. How to check and configure your server.

Guide to checking open ports: TCP/UDP, common ports, scanning tools, security risks, and best practices for hardening your server.

Complete guide to WHOIS lookups: how to find domain ownership, registration dates, expiry times. Examples, tools, and practical applications.

Why your site doesn't work after a DNS change, how long the update really takes and how to speed it up. TTL, resolver caches, dig checks and common migration mistakes.

Complete guide to website monitoring: uptime, SSL, DNS, speed. How to choose check intervals, set up alerts, and never miss a downtime.

What is Content Security Policy, how to configure the CSP header, which directives to use. Configuration examples and common mistakes.

How to check a website's SSL certificate: step by step in Chrome, Firefox and Safari, with openssl and curl, or using an online checker. Certificate fields, the trust chain, a common errors table, and automated expiry monitoring.

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.

How to check hundreds of URLs at once: batch HTTP status code, header, and redirect verification. Tools and automation.