01DNS propagation7 min
How Long Does DNS Propagation Take?
Learn what controls DNS propagation time, how TTL and resolver caches interact, and how to verify a DNS change worldwide.
Read guideDNS knowledge base
DNS guides for real incidents and migrations.
Original, practical explanations for diagnosing propagation, resolver errors, email authentication and DNS changes. Every guide includes commands you can run and links to the relevant global checker.
02Troubleshooting8 min
DNS Propagation Not Working? A Step-by-Step Checklist
Diagnose a DNS change that is not appearing by checking authoritative servers, delegation, TTL, DNSSEC and resolver caches.
Read guide03DNS errors7 min
NXDOMAIN vs SERVFAIL: What Each DNS Error Means
Understand the difference between NXDOMAIN and SERVFAIL, identify their common causes, and diagnose each response with dig.
Read guide04Email DNS9 min
How to Check SPF, DKIM and DMARC DNS Records
Use dig and global TXT lookups to verify SPF, DKIM and DMARC records and avoid common email authentication mistakes.
Read guide05DNS fundamentals7 min
DNS TTL Explained: Caching, Propagation and Best Practices
Understand DNS TTL values, how recursive caches count them down, and which TTL to use before and after a migration.
Read guide06DNS errors9 min
How to Fix DNS SERVFAIL Errors
Troubleshoot DNS SERVFAIL by checking delegation, authoritative reachability, DNSSEC signatures, DS records and zone consistency.
Read guide07DNS records7 min
CNAME vs A Record: Differences and When to Use Each
Compare CNAME and A records, understand alias resolution, apex-domain limitations and the right choice for websites and services.
Read guide08Migrations9 min
How to Check DNS After a Website or Server Migration
Use a repeatable DNS migration checklist to verify nameservers, A and AAAA records, mail, TTL, TLS and global resolver answers.
Read guide