Articles & Guides
Useful resources for web developers and system administrators
DNS
Wildcard DNS Records: Use Cases and Pitfalls
Wildcard DNS (*.example.com): use cases, RFC 4592 constraints, conflicts, performance, and security implications.
DNS
Reverse DNS and PTR Records: Why You Need Them
What rDNS and PTR records are. Setting up in-addr.arpa reverse zones, PTR for mail servers, and the impact on SPF and email deliverability.
DNS
DNS Leak: What It Is, How to Test and Fix
DNS leak on VPN — what it is, why it matters, and how to fix it. Step-by-step tests and fixes for Windows, macOS, Linux, iOS, Android.
DNS
Types of DNS Servers Explained: Recursive, Authoritative, Root
How DNS servers work: root, TLD, authoritative, recursive, and caching. Complete picture of DNS resolution with examples and tools.
DNS
DNS TTL Best Practices: Optimal Values for Different Records
DNS TTL best practices: optimal values for A, MX, NS, TXT. How TTL affects migrations, failover, and load on your authoritative DNS.
DNS
MX Records for Email: Step-by-Step Setup Guide
Full MX records setup for Google Workspace, Yandex 360, Zoho. Priority, RFC 5321, SPF/DKIM/DMARC, and delivery testing.
DNS
CNAME vs A Record: Differences and When to Use Each
CNAME or A record? Detailed comparison: performance, RFC 1034/1912 constraints, apex domain, CDN, and when each one is the right choice.
DNS
How to Flush DNS Cache: Windows, Mac, Linux, Browsers
Complete guide to flushing DNS cache — commands for Windows, macOS, Linux, Chrome, Firefox, Safari. When you need it and why it may not work.
DNS
How to Check DNS Propagation: 5 Tools and Methods
Check DNS propagation in 2026: 5 best tools, how propagation actually works, dig/nslookup commands, and how to speed it up.
DNS
DNS Not Resolving: 8 Causes and How to Fix
DNS not resolving and the site is down? Learn 8 common causes — from TTL and cache to NS and firewall — with step-by-step diagnostics and tools.