Query public DNS records from a server-side resolver
DNS Lookup lets you inspect public DNS records without relying only on the cache or interface of your local resolver. Enter a domain name, choose a record type and SubnetMaster sends the query from its backend. The result includes the returned owner name, TTL and record data so you can inspect what a public resolver currently sees.
The tool supports A, AAAA, CNAME, MX, TXT, NS, PTR, SOA, SRV and CAA. That covers common address records, aliases, mail routing, verification records, authoritative delegation, reverse DNS and service/security metadata. For the underlying resolution process, read the DNS guide.
How to use DNS Lookup
Enter a name such as subnetmaster.es, select a type and press Query DNS. For PTR queries you can paste an IPv4 or IPv6 address directly; the tool converts it to the corresponding in-addr.arpa or ip6.arpa reverse name before sending the query.
An empty answer does not necessarily mean that the domain does not exist. It can simply mean that the requested record type is not published. Test the specific record that matches the problem you are investigating instead of assuming every hostname should have every type.
What each DNS record type is used for
| Type | Typical purpose | Useful check |
|---|---|---|
| A | IPv4 address | Which IPv4 address a hostname resolves to. |
| AAAA | IPv6 address | Whether IPv6 is published for the name. |
| CNAME | Alias | Whether a name points to another canonical hostname. |
| MX | Mail exchange | Which mail servers and priorities receive mail. |
| TXT | Text metadata | SPF, verification tokens and other policy/ownership data. |
| NS | Authoritative nameservers | Which servers are delegated for a zone. |
| PTR | Reverse DNS | Which name, if any, is associated with an IP address. |
| SOA / SRV / CAA | Zone, service and CA policy data | Administrative, service-discovery and certificate-authority checks. |
TTL, caching and the idea of DNS propagation
The TTL (Time To Live) tells recursive resolvers how long they may cache a record before asking again. After changing DNS, different users can temporarily receive different answers because their resolvers cached the previous value at different times. What is often called “DNS propagation” is largely the interaction between authoritative updates, resolver caches and TTL expiry.
The TTL shown here helps you interpret a recent change. If you are moving a site or troubleshooting a cutover, compare DNS with the actual network endpoint. The public IP checker and IP geolocation tool can provide additional context when you need to identify the network behind an address.
Reverse DNS with PTR records
PTR works in the opposite direction from A or AAAA: instead of mapping a name to an address, it looks for a name under the reverse-DNS hierarchy for an IP. Reverse records are controlled by the organization responsible for the address space, not simply by whoever controls a normal forward DNS zone.
PTR is particularly relevant to mail infrastructure, logging and diagnostics. A missing PTR is not automatically a connectivity failure, but some services use reverse DNS as one part of their trust or identification process.
How to troubleshoot DNS with this tool
Start with the symptom. If a website name does not resolve, query A and AAAA. If mail delivery is involved, inspect MX and relevant TXT records. If delegation looks wrong, query NS and SOA. If a service relies on discovery records, inspect SRV. For certificate-issuance policy, use CAA. Compare the answers with the configuration you expect and note the TTL before making assumptions about stale data.
DNS is only one layer of connectivity. If records look correct but the application still fails, continue with the network troubleshooting guide and verify routing, ports, firewall behavior and the destination service.
Resolver and result limitations
This tool uses a public server-side DNS-over-HTTPS resolver. Its answer represents what that resolver sees, which can differ from an internal corporate resolver, split-horizon DNS view, local hosts file or ISP-specific cache. DNSSEC validation details, zone transfers and authoritative trace operations are outside the scope of this simple lookup interface.
Use it as a fast public-DNS check, not as a replacement for every diagnostic tool. For production incidents, comparing more than one resolver and querying authoritative servers directly can help distinguish stale cache from authoritative configuration.
Frequently asked questions
Why does DNS Lookup return no answers?
The query can be valid even when that specific record type is not published. Try the record type that matches the service you are checking.
Can I use an IP address for a PTR lookup?
Yes. Paste the IPv4 or IPv6 address and the tool generates the corresponding reverse-DNS query name automatically.
Does a low TTL make DNS updates instant?
No. A low TTL reduces how long caches may retain a record, but authoritative updates, existing cached responses and resolver behavior still affect when users observe a change.
Why can this result differ from my office network?
Corporate environments may use internal or split-horizon DNS. This tool queries a public resolver, so private/internal records and policies may not match.