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 guide09Email DNS7 min
How to Check an MX Record for a Domain
Learn how to check MX records, understand mail server priority and diagnose missing or stale mail routing after an email migration.
Read guide10Email DNS8 min
How to Check an SPF Record
Check SPF TXT records with dig, spot duplicate policies, understand include mechanisms and diagnose email authentication failures.
Read guide11Reverse DNS7 min
What Is Reverse DNS and Why PTR Records Matter
Understand reverse DNS, PTR records, forward-confirmed reverse DNS and why mail servers often require a valid PTR hostname.
Read guide12DNS basics9 min
DNS Record Types Explained: A, AAAA, CNAME, MX, TXT, NS and More
A practical explanation of common DNS record types, what each one does and which checker to use when troubleshooting.
Read guide13Migrations8 min
Common DNS Migration Mistakes and How to Avoid Them
Avoid stale records, missing mail DNS, broken IPv6, DNSSEC failures and cache surprises during website or DNS provider migrations.
Read guide14DNSSEC9 min
How to Diagnose DNSSEC SERVFAIL with dig
A practical DNSSEC troubleshooting workflow for SERVFAIL responses, DS mismatches, broken signatures and resolver validation differences.
Read guide15Cloud DNS8 min
Cloudflare and Vercel DNS Checklist
A practical checklist for connecting a domain to Vercel through Cloudflare DNS, including apex records, www redirects, proxy mode and propagation checks.
Read guide16Email DNS8 min
Google Workspace MX Migration Checklist
Check Google Workspace MX, SPF, DKIM and DMARC records during an email migration and avoid cached delivery to the old provider.
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