DNS lookup
What a DNS lookup shows
The Domain Name System (DNS) is the internet's address book. It turns names like example.com into the IP addresses of servers, tells the world where a domain's email should be delivered, and stores text records used to prove ownership and protect against spoofing. A DNS lookup asks the DNS for a domain's records and shows you the answers.
Use it to confirm a website points at the right server after moving hosts, check that email is routed to Google Workspace or Microsoft 365, verify a TXT record a service asked you to add, or investigate a domain before buying it or trusting an email from it.
Record types
DNS record types explained
| Record | What it does | Example |
|---|
| A | Points a name at an IPv4 address | 93.184.215.14 |
| AAAA | Points a name at an IPv6 address | 2606:2800:21f:cb07::1 |
| CNAME | Makes one name an alias of another | www to example.com |
| MX | Mail servers for the domain, lowest priority number first | 1 smtp.google.com |
| NS | The name servers that are authoritative for the domain | ns1.cloudflare.com |
| TXT | Free text: SPF, domain verification, DKIM and more | v=spf1 include:_spf.google.com ~all |
| SOA | Zone details: primary server, admin contact, serial and timers | ns1... hostmaster... serial 2026110501 |
| CAA | Which certificate authorities may issue SSL certificates | 0 issue "letsencrypt.org" |
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SPF and DMARC
SPF and DMARC email security check
Email authentication records stop other people sending mail that pretends to come from your domain, and since 2024 Gmail and Yahoo require them for bulk senders.
- SPF is a TXT record starting with
v=spf1 that lists the servers allowed to send your email. A domain must have only one SPF record; two records make SPF fail. A record ending in +all or ?all allows anyone, which defeats the purpose. Use ~all (soft fail) or -all (hard fail).
- DMARC is a TXT record at
_dmarc.yourdomain.com starting with v=DMARC1. It tells receivers what to do with mail that fails SPF and DKIM. p=none only monitors, p=quarantine sends failures to spam and p=reject blocks them.
The tool flags missing SPF, duplicate SPF, overly permissive SPF, missing DMARC and DMARC at p=none. DKIM keys live at selector names that vary by provider, so look them up as a TXT record on selector._domainkey.yourdomain.com.
Bulk DNS lookup
Bulk DNS lookup for many domains
Switch to Bulk Domains and paste up to 50 domains to audit a whole portfolio in one table: where each one is hosted, which mail provider it uses, which name servers it is on, and whether email authentication is set up. Export the full list of records to CSV for documentation or a migration plan.
Results come from public recursive DNS at the moment you run the check. If you recently changed a record, some resolvers may still return the old value until its TTL expires, so wait for the TTL and check again. Related tools: see registration and expiry dates with the domain age checker, check certificates with the SSL checker, and confirm addresses on a domain accept mail with the email validator.
Propagation
DNS changes and propagation
When you change a record, the new value is live on your DNS provider immediately, but resolvers around the world may keep the old answer until its TTL runs out. Lower the TTL to 300 seconds a day before a planned move, make the change, confirm it here, and raise the TTL again afterwards.
FAQ
DNS Lookup: frequently asked questions
What is a DNS lookup?
A DNS lookup queries the Domain Name System for a domain's records, such as its IP address (A), mail servers (MX), name servers (NS) and text records (TXT).
How do I check the DNS records of a domain?
Enter the domain, tick the record types you want and click Look Up DNS. Each record is shown with its value and TTL.
How do I find a domain's mail server?
Look at its MX records. The server with the lowest priority number is tried first.
How do I check SPF and DMARC?
Keep Check email security ticked. The tool reads the SPF TXT record and the _dmarc TXT record and flags common problems.
Why do I see old DNS values after a change?
Resolvers cache records for the TTL period. Wait until the TTL has passed and check again.
Can I look up many domains at once?
Yes. Bulk Domains checks up to 50 domains and exports all records to CSV.
What is a CAA record?
A CAA record lists the certificate authorities allowed to issue SSL certificates for the domain. If none exists, any CA may issue.
Is this DNS lookup free?
Yes. It is free with no sign-up and no limit on how often you use it.