DNS fundamentals, troubleshooting, security, and practical workflows -- written by the team that builds this tool.
Two genuinely different moments
dig / nslookup
Full protocol detail, scriptable, offline
Web-based tool
No setup, bulk lookups, shareable
Learn how to use a DNS lookup tool to check a domain's address, mail, nameserver, alias, and text records, then interpret the answers safely.
The records you will meet in nearly every zone
Use a DNS checker to inspect A, AAAA, CNAME, MX, NS, and TXT records, compare answers, and diagnose common DNS configuration issues.
Two addressing schemes, running side by side
IPv4
192.0.2.10
32 bits -- ~4.3 billion addresses -- exhausted
IPv6
2606:4700::6810:84e5
128 bits -- 340 undecillion addresses
Find a domain's public IPv4 and IPv6 addresses, understand A and AAAA answers, and learn why DNS may return several valid IP addresses.
Three layers share the name "DNS server"
Stub resolver
your own device
Recursive resolver
ISP, router, or 1.1.1.1
Authoritative
the domain's own DNS
Understand domain IP address lookup results, including multiple addresses, IPv4 and IPv6 records, CDN edges, and the limits of reverse attribution.
Three layers share the name "DNS server"
Stub resolver
your own device
Recursive resolver
ISP, router, or 1.1.1.1
Authoritative
the domain's own DNS
Learn what DNS servers do, how recursive resolvers differ from authoritative nameservers, and how to identify which server answered a query.
A recursive DNS lookup, one hop at a time
Browser
wants example.com
Resolver
your ISP / 1.1.1.1
Root + TLD
who runs .com?
Authoritative
the real answer
Every hop down this chain is itself a DNS lookup, cached afterward
Follow a DNS query through caches, recursive resolvers, referrals, and authoritative servers to understand how a hostname becomes an address.
The records you will meet in nearly every zone
Understand the DNS SOA record, its serial number, refresh and retry timers, and how it helps authoritative nameservers coordinate a zone.
The records you will meet in nearly every zone
Learn how DNS Certification Authority Authorization records name permitted certificate issuers and how to avoid common CAA configuration mistakes.
Three roles, often three different companies
Understand NS records, parent-zone delegation, authoritative nameservers, and how to confirm which DNS provider serves a domain's records.
A recursive DNS lookup, one hop at a time
Browser
wants example.com
Resolver
your ISP / 1.1.1.1
Root + TLD
who runs .com?
Authoritative
the real answer
Every hop down this chain is itself a DNS lookup, cached afterward
Learn what DNSSEC signatures, DS and DNSKEY records do, how validation works, and how misconfiguration can cause SERVFAIL responses.
The records you will meet in nearly every zone
Learn how DNS zone files organize records, owner names, TTLs, and record data, with a safe checklist for reviewing or migrating a zone.
Every IPv4 range has an IPv6 equivalent
Check a domain's AAAA record, distinguish IPv6 DNS publication from IPv6 connectivity, and troubleshoot common dual-stack configuration gaps.