DNS lookup
Records for a name, or the name behind an address.
Runs on our server; the query is not stored.
What you can look up#
| Type | What it answers |
|---|---|
| A, AAAA | The IPv4 and IPv6 addresses a name points to |
| MX | Where email for the domain is delivered, in priority order (lowest number first) |
| NS | The name servers that are authoritative for the domain |
| TXT | Text records: SPF and DKIM email policy, and domain-ownership tokens |
| CNAME | An alias: the name is another name in disguise |
| SOA | Zone administration data: the primary server, contact and serial number |
| CAA | Which certificate authorities may issue certificates for the domain |
The Reverse tab looks up the PTR record for an IP address: the hostname its owner published for it.
Reading the answers#
- TTL is how many seconds a resolver may keep the answer. A short TTL means changes take effect quickly. A long one means a change can take that long to reach everyone.
- Several answers for one name are normal. Busy sites publish many addresses, and resolvers rotate through them.
- MX priority works backwards:
10is tried before20. - A `TXT` starting `v=spf1` is the SPF policy, listing the servers allowed to send mail for the domain.
Common jobs for this tool#
- Check where a domain's mail goes, before or after a migration.
- See whether a DNS change is visible yet, by comparing the record with the one you set. Remember the TTL.
- Find the name servers, so you know where to make a change.
- Read the SPF record when mail is being rejected.
- See the CAA record before ordering a certificate.
- Find out what name an address reverses to, when reading a log.
Where the lookup runs#
The query is sent from this site's server, not from your device, and is not stored. The answer is therefore what our resolver sees, which can differ from what your own resolver or a VPN returns, especially for names that answer differently by location. To follow the path a lookup takes, and to see why answers get cached, read how a DNS lookup works.
Related guides
- What is DNS and how does a DNS lookup work?DNS turns names like example.com into IP addresses. The five steps of a lookup, the record types you will meet, and how to run a DNS lookup yourself.
- Reverse DNS and PTR recordsReverse DNS maps an IP address back to a hostname using PTR records. How the in-addr.arpa lookup works, why mail servers check it, and how to run one.