Quick answer
Enter a domain (for example example.com) and press “Look up”: you get its A / AAAA records (website IP), MX (mail servers), NS (where DNS is managed), TXT (SPF, DMARC, verification codes), CNAME, SOA and CAA, each with its TTL. Press “Check DMARC” to see the domain's email anti-spoofing policy.
What is DNS?
This tool reads a domain's public DNS records from the Công Cụ Nhanh server. It helps when you have just pointed a domain at new hosting, set up business email, verified a domain with Google or Facebook, or need to find out why your email lands in spam. Common TXT records such as SPF, DMARC and DKIM are recognised and explained, and accented domain names are converted to punycode automatically.
How to look up DNS records
- 1
Type a domain into “Domain”. You can paste a full URL (https://www.example.com/page); the domain part is extracted for you.
- 2
Keep all eight record types or pick only the ones you need (just MX when checking email, for example).
- 3
Press “Look up”. Each record type appears in its own panel with a short explanation and its cache time (TTL).
- 4
For email: check MX and the TXT line labelled SPF, then press “Check DMARC” to look up the domain's _dmarc record.
- 5
Click “Copy” next to any value you need to send to your hosting or email provider.
DNS record types
| Record | Used for | Example value |
|---|---|---|
| A | Points the domain at a web server's IPv4 address | 160.22.106.166 |
| AAAA | Points the domain at an IPv6 address | 2402:800:… |
| CNAME | An alias, e.g. www following the main domain | www → example.com |
| MX | Mail servers; lower priority numbers are tried first | 1 smtp.google.com |
| NS | Name servers that manage the domain | ns1.provider.net |
| TXT | SPF, DMARC, DKIM, service verification codes | v=spf1 include:_spf.google.com ~all |
| SOA | Zone administration details | ns1.provider.net, serial 2026102101 |
| CAA | Who may issue SSL certificates | 0 issue "letsencrypt.org" |
The email authentication trio
| Record | Where | What it means |
|---|---|---|
| SPF | TXT on the domain, starting with v=spf1 | Lists servers allowed to send mail for the domain; ~all flags and -all rejects anything else |
| DKIM | TXT at selector._domainkey.domain | The public key used to check the email's digital signature |
| DMARC | TXT at _dmarc.domain, starting with v=DMARC1 | What to do when SPF / DKIM fail: none (monitor), quarantine (spam), reject |
Gmail and Yahoo require bulk senders to have SPF, DKIM and DMARC; without them email is far more likely to land in spam.
Real-world examples
New hosting, old site still showing
Look up the A record: if it still shows the old IP, the record hasn't changed yet or is cached for its TTL (a 1-hour TTL means waiting up to about an hour).
Setting up Google Workspace
MX should show smtp.google.com; TXT should include google-site-verification=… for domain verification, and an SPF line with include:_spf.google.com.
Outgoing email goes to spam
Check that TXT has an SPF record, then press “Check DMARC”. With no DMARC, ask your admin to add v=DMARC1; p=none to start monitoring.
Not sure where DNS is managed
Look up NS: if it shows *.ns.cloudflare.com, records are edited at Cloudflare, not where you bought the domain.
Common problems
- I changed a record but still see the old value.
- DNS is cached for its TTL in many places, so wait for the old TTL to expire. Also make sure you edited it where DNS is actually hosted (see the NS records).
- Two SPF records.
- A domain may have only one record starting with v=spf1; merge the includes into a single line or SPF will fail.
- _dmarc shows “No records”.
- The domain has no DMARC policy yet. Add a TXT record at _dmarc with v=DMARC1; p=none; rua=mailto:you@example.com.
- “That doesn't look like a valid domain”.
- Check for typos, spaces or extra dots. IP addresses and internal names like localhost or printer.local are not looked up.
- Too many lookups.
- To prevent abuse, each person can make 30 lookups every 5 minutes. Wait a few minutes and try again.
How the lookup works
The Công Cụ Nhanh server asks the normal DNS resolver (just like opening a website would) and returns the domain's public records. It only reads DNS: it never connects to the domain's website or servers and does not store the domains you look up.
Results can differ from elsewhere by a few minutes because every DNS server caches records for their TTL. The TTL shown next to each record tells you how long a change takes to spread.
Glossary
- DNS
- The Domain Name System turns readable names (example.com) into the IP addresses computers use.
- TTL
- How long (in seconds) a record may be cached before it is asked for again; shorter TTLs make changes spread faster.
- Punycode
- The ASCII form of an accented domain name, e.g. tênmiền.vn becomes xn--tnmin-hsa0954c.vn.
- DNS propagation
- The time it takes for a new record to replace cached copies of the old one everywhere, set by the old TTL.
- DKIM selector
- A name chosen by the email service (e.g. google) used to find the DKIM key at selector._domainkey.domain.
Frequently asked questions
Can I look up any domain?
Any public domain (.com, .net, .vn, .co.uk…), including accented international domain names.
Why are the results different from my computer?
Your computer and the lookup server may hold different cached copies; once the TTL expires they will match.
How do I see a DKIM record?
DKIM lives at selector._domainkey.domain; enter the full name, such as google._domainkey.example.com, choose TXT and look it up.
Does it do WHOIS (domain owner) lookups?
No. It only reads DNS records; check ownership on your registrar's WHOIS page.
Is there a lookup limit?
30 lookups per 5 minutes per person, so the server can't be abused; normal use never gets close.
Are the domains I look up stored?
No. The server only counts requests for rate limiting, using a hash that does not contain your IP address.
Ratings and comments
Loading…