How to Do a DNS Lookup Online

DNS lookups are something developers, sysadmins, and IT teams do dozens of times a week — verifying record propagation, debugging email issues, checking nameservers before a migration, or investigating a suspicious domain.

Check any domain's DNS records instantly with our WHOIS Lookup tool.

Using dig — The Standard Tool

Basic A record lookup

dig toolchecking.com A +short

Query a specific DNS server

dig @8.8.8.8 toolchecking.com A +short dig @1.1.1.1 toolchecking.com A +short

Querying specific resolvers lets you compare what different parts of the world see — useful during propagation.

Check MX records

dig toolchecking.com MX +short

Check TXT records (SPF, DMARC)

dig toolchecking.com TXT +short dig _dmarc.toolchecking.com TXT +short

Trace full resolution path

dig toolchecking.com +trace

Shows every step from root server to authoritative nameserver. Invaluable for debugging unexpected results.

Using nslookup — Windows Native

nslookup works on Windows without installing anything:

nslookup toolchecking.com nslookup -type=MX toolchecking.com nslookup -type=TXT toolchecking.com

Less flexible than dig but always available on Windows.

Browser-Based DNS Lookup

When you don't have terminal access — checking a client site, using a shared machine, or working from a locked-down environment — use a browser-based tool:

Look up DNS records, nameservers and domain registration for any domain

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FAQs

Your browser has its own DNS cache separate from the OS. Chrome caches DNS for a minimum of 1 minute regardless of TTL. Clear Chrome's DNS cache at chrome://net-internals/#dns and reload to see the current result.
Query multiple major resolvers: dig @8.8.8.8 (Google), dig @1.1.1.1 (Cloudflare), dig @9.9.9.9 (Quad9). If all three return the new value, propagation is essentially complete for most users worldwide.
NXDOMAIN (Non-Existent Domain) means the domain does not exist in DNS — either never registered, registration expired, or deleted. Different from a domain that exists but has no A record pointing to a server.
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