What is a DNS lookup?
Quick answerA DNS lookup asks the Domain Name System which records a domain publishes: A and AAAA (IP addresses), CNAME (aliases), MX (mail servers), NS (nameservers), TXT (verification, SPF, DMARC) and more. It is the first step in debugging a website that will not load or email that will not arrive.
Record types explained
| Record | What it does | Typical problem it reveals |
|---|---|---|
| A / AAAA | Points the name to an IPv4 / IPv6 address | Site still pointing at an old host |
| CNAME | Makes one name an alias of another | www not set up, or a CNAME clashing with other records |
| MX | Lists the mail servers that accept email | Email bouncing after a provider change |
| NS | Names the servers authoritative for the zone | Changes made at the wrong DNS provider |
| TXT | Free text: SPF, DMARC, site verification | Missing SPF/DMARC, duplicate SPF records |
| SOA | Zone metadata (primary server, serial) | Serial not updating after edits |
| CAA | Which certificate authorities may issue SSL | SSL issuance blocked by a CAA rule |
Is my DNS change live yet?
Pick a single record type and the tool asks two independent public resolvers (Cloudflare 1.1.1.1 and Google 8.8.8.8). If they disagree, the old value is still cached somewhere: wait for the record's TTL to pass. Lower the TTL a day before a planned change to make future switches faster.
Common fixes
- Site not loading after moving hosts: update the A record (or CNAME) at the provider listed in your NS records, not at your old host.
- Email stopped working: check the MX records match your email provider's instructions exactly, including priorities.
- "Domain not verified": make sure the TXT record sits on the exact name requested (root or a subdomain).
Dns lookup FAQ
Is this dns lookup free?
Yes, unlimited and free with no sign-up. Queries go from your browser to public DNS-over-HTTPS resolvers (Cloudflare and Google).
Why do two resolvers show different results?
DNS answers are cached for the record's TTL. Right after a change, some resolvers still serve the old value. Wait for the TTL to expire and check again.
Can I look up a subdomain?
Yes. Type the full name, for example mail.example.com or _dmarc.example.com.