Why do different DNS resolvers return different results?

DNS changes propagate gradually — each resolver's cache reflects when it last looked up the record. High TTL records take longer to propagate. Use multiple resolvers to check propagation status; when all return the new value, propagation is complete.

What is the difference between A and CNAME records?

An A record maps a hostname directly to an IP address. A CNAME maps a hostname to another hostname (an alias). When a browser resolves a CNAME, it follows the chain until it finds an A record. Root domains (example.com without www) cannot use CNAME records.

What are DNS TXT records used for?

TXT records hold arbitrary text data, most commonly: SPF (sender policy framework for email anti-spoofing), DKIM keys (email signing), DMARC policies, domain ownership verification (Google Search Console, SSL issuers), and various SaaS service verification.

DNS Query Builder | DevTools Surf

DevTools Surf

Example: DNS Query Builder

A worked example, rendered from real sample data. Sign in to run the tool on your own input.

Input

example.com
A,AAAA,MX,TXT,NS,CAA

Output

═══ What this tool did ═══
ℹ No DNS query was sent. This page runs offline and makes no outbound network calls.
ℹ It validates the name, builds the exact resolver commands to run, and explains any answer section you paste back in.

═══ Name ═══
Query name: example.com
Labels: 2 (example · com)
Length: 11 of 253 bytes
Registrable guess: example.com
✓ The name is syntactically valid for a DNS query.

═══ Commands to run (Cloudflare) ═══
  dig @1.1.1.1 example.com A +noall +answer
  dig @1.1.1.1 example.com AAAA +noall +answer
  dig @1.1.1.1 example.com MX +noall +answer
  dig @1.1.1.1 example.com TXT +noall +answer
  dig @1.1.1.1 example.com NS +noall +answer
  dig @1.1.1.1 example.com CAA +noall +answer
  dig @1.1.1.1 example.com ANY +noall +answer   (most servers refuse ANY — RFC 8482)
  dig +trace example.com                     follow the delegation from the root
  dig example.com NS @$(dig +short example.com NS | head -1)  ask the authoritative server directly
  nslookup -type=A example.com 1.1.1.1
  host -t A example.com 1.1.1.1
  resolvectl query example.com               systemd-resolved, shows which link answered
  curl -sH 'accept: application/dns-json' 'https://cloudflare-dns.com/dns-query?name=example.com&type=A'
  dig example.com SOA +short                 confirm you are looking at the right zone

═══ Record types you asked for ═══
─── A ───
• IPv4 address of the name.
• Use it to find which IPv4 host serves a name.
─── AAAA ───
• IPv6 address of the name.
• Missing AAAA is the usual cause of "no IPv6" reports.
─── MX ───
• Mail exchangers with a preference numb
…

About DNS Query Builder

DNS Query Builder preview - Networking tool

Build dig/nslookup/resolvectl commands for a domain and decode the answer section you paste back (no lookup is performed). Part of the DevTools Surf developer suite. Browse more tools in the Networking collection.

Use Cases

Verify DNS propagation after changing A records for a domain migration
Debug email delivery issues by checking MX and SPF/DKIM TXT records
Identify which nameservers are authoritative for a domain
Diagnose CDN configuration by checking CNAME chains

Tips

Query specific record types using the selector: A (IPv4), AAAA (IPv6), MX (mail), TXT (SPF, DKIM), CNAME, NS, and SOA — 'all' is useful for a complete audit
Compare results from multiple resolvers (Google 8.8.8.8, Cloudflare 1.1.1.1, your ISP) to diagnose DNS propagation delays or resolver-specific issues
The TTL field in results tells you how long resolvers will cache the record — a low TTL (60-300s) is appropriate before a DNS change; restore to normal (3600-86400s) afterward

Fun Facts

DNS (Domain Name System) was invented by Paul Mockapetris in 1983. Before DNS, host-to-IP mappings were maintained in a single HOSTS.TXT file distributed via FTP — by 1982 the file had grown too large for manual maintenance.
There are 13 root DNS server clusters worldwide (labeled A through M), but each cluster uses anycast routing to hundreds of physical servers. The total number of root server instances globally exceeds 1,800 — making DNS one of the most distributed systems in computing.
DNS over HTTPS (DoH) was standardized in RFC 8484 (2018) and encrypts DNS queries to prevent ISP interception and eavesdropping. Browser-based DoH (Mozilla, Chrome) bypasses the OS resolver entirely — a change that fragmented traditional enterprise DNS filtering.

FAQ

Why do different DNS resolvers return different results?: DNS changes propagate gradually — each resolver's cache reflects when it last looked up the record. High TTL records take longer to propagate. Use multiple resolvers to check propagation status; when all return the new value, propagation is complete.
What is the difference between A and CNAME records?: An A record maps a hostname directly to an IP address. A CNAME maps a hostname to another hostname (an alias). When a browser resolves a CNAME, it follows the chain until it finds an A record. Root domains (example.com without www) cannot use CNAME records.
What are DNS TXT records used for?: TXT records hold arbitrary text data, most commonly: SPF (sender policy framework for email anti-spoofing), DKIM keys (email signing), DMARC policies, domain ownership verification (Google Search Console, SSL issuers), and various SaaS service verification.

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