DNS Lookup

Read DNS answers without leaving the browser

This DNS lookup tool asks Google Public DNS for selected resource records and presents the answers as a compact table. Enter a hostname, choose one or more of A, AAAA, CNAME, MX, TXT, and NS, then read the returned value and TTL. It is useful when a deployment points at the wrong address, mail delivery fails, ownership verification is pending, or a delegated zone does not appear to use the expected name servers.

This is a live network tool, not an offline parser. The browser sends a DNS-over-HTTPS request to https://dns.google/resolve for every selected type. Google therefore receives the queried hostname along with connection metadata such as your public IP address. DevsTool does not proxy those requests, and the component does not send the answers to a DevsTool backend. Do not use the lookup for a sensitive internal hostname that should not be disclosed to a public resolver.

A practical lookup sequence

Start with a bare hostname such as app.example.com, not a complete URL. Do not include https://, a port, a path, or query parameters. Select only the record families relevant to the question; fewer selections make the answer easier to interpret and reduce requests.

1. Choose A and AAAA when checking where a web host resolves over IPv4 and IPv6.
2. Choose CNAME when the hostname is expected to alias a CDN, load balancer, or managed platform.
3. Choose MX to inspect the mail exchangers published for a domain.
4. Choose TXT for SPF, domain verification, and other text-based policy records.
5. Choose NS to see authoritative name-server delegation returned in the answer.
6. Wait briefly after typing. The tool uses a 300 ms delay and then runs one HTTPS query per selected type. Refresh starts the same lookup immediately.

The initial selection includes A, AAAA, MX, and TXT. Clicking a type toggles it. Clearing the hostname or deselecting every type clears the results rather than issuing a request.

What each row means

Type identifies the resource-record format. An A value is a 32-bit IPv4 address such as 203.0.113.20; an AAAA value is a 128-bit IPv6 address such as 2001:db8::20. A CNAME value is another DNS name. It is an alias relationship, not an HTTP redirect, and the browser must still resolve the target name before connecting.

An MX value normally contains a preference number and mail-server hostname. Lower preference values are tried before higher ones. Publishing an MX row does not prove that SMTP is reachable, that the server accepts a particular recipient, or that SPF and DKIM are correct. NS answers identify name servers, but the absence of an NS row for a nested hostname may simply mean delegation exists at the parent zone rather than at that exact name.

TXT data is flexible. A row beginning v=spf1 is an SPF policy; other values may prove control to a cloud provider or certificate authority. The UI removes one pair of surrounding double quotes from each TXT answer for readability. Long TXT records can be represented by DNS as multiple quoted character strings, so use a full DNS client such as dig when exact wire-level quoting and segment boundaries matter.

TTL is the time to live supplied in seconds. It tells recursive resolvers how long they may cache that answer. A TTL of 300 permits caching for five minutes. It is not a countdown synchronized across the Internet: different resolvers may have cached the old answer at different moments, and browser, operating-system, ISP, or application caches can add their own behavior.

Worked diagnosis: a cutover that looks inconsistent

Suppose shop.example.com is moving from 198.51.100.10 to 198.51.100.42. Select A and CNAME. If A returns the old address with TTL 3600, the authoritative data visible through Google Public DNS has not changed or is still cached. If the new A address appears but users still reach the old site, check local caches, another recursive resolver, and the CDN configuration. If CNAME returns shops.platform.example. instead, investigate the target’s A and AAAA records rather than expecting an address on the alias itself.

Now select AAAA. An unexpected IPv6 record can explain why only some networks reach the old origin: IPv6-capable clients may prefer AAAA while IPv4-only clients use A. Removing or correcting AAAA is often as important as changing A during a migration.

For mail, enter example.com and select MX and TXT. Read MX preference and hostnames, then inspect SPF in TXT. A valid-looking result only confirms publication. Delivery can still fail because of SMTP filtering, missing PTR records, DKIM problems, DMARC policy, or an unreachable port 25.

DNS terminology that prevents wrong conclusions

An authoritative server stores zone data. A recursive resolver follows referrals and caches answers for clients. This online DNS lookup uses Google’s recursive DNS-over-HTTPS service; it does not directly query a chosen authoritative server and offers no resolver selector. Consequently, it is excellent for seeing what one major public resolver currently returns, but it cannot compare propagation across providers by itself.

NXDOMAIN means the queried name does not exist. NOERROR with no answers can mean the name exists but has no record of the requested type. The component does not display DNS status codes separately. For each type, nonzero statuses and empty answer sections are skipped; if nothing remains across all selected types, the page reports “No records found for the selected types.” That message therefore combines several possibilities and should not be treated as proof of NXDOMAIN.

DNS responses may also include records needed to follow an alias. The table includes only supported answer types, so SOA records, DNSSEC signatures, CAA, SRV, PTR, HTTPS/SVCB, and other types are not shown. The tool does not expose authority or additional sections, flags such as AD or CD, the responding server, query time, or DNSSEC validation details.

Troubleshooting an empty or failed result

First remove URL syntax and try the registrable domain. https://example.com/login is not a valid hostname input for this component. Check spelling, internationalized-domain representation, and whether a trailing dot or whitespace is causing unexpected resolver behavior. The host is URL-encoded but otherwise passed to the API; it is not extensively normalized or validated.

If only one type is empty, that can be normal. Many domains have no AAAA or CNAME, and a host that has A records generally cannot also have a CNAME at the same owner name. If every selected type is empty, compare with dig example.com A or your operating system’s nslookup to distinguish public DNS data from browser or service issues.

A message such as DNS query failed (429) points to an HTTP failure from the DNS-over-HTTPS endpoint, possibly rate limiting. A blocked cross-origin request, privacy extension, enterprise policy, captive portal, or lost connection can also prevent fetch from completing. Because selected queries run sequentially, one HTTP error stops the remaining sequence and clears accumulated rows. Reduce rapid edits, retry later, or query with a local command-line client.

Privacy, caching, and browser boundaries

The hostname leaves the page directly for Google Public DNS. The request uses HTTPS, which protects it in transit from ordinary network observation, but the resolver still sees it. Returned rows live in React state and are not persisted by this tool. Normal browser and resolver logging or caching policies remain outside the component’s control.

Browsers cannot send classic DNS packets over UDP or TCP port 53 from page JavaScript, which is why the tool relies on a DNS-over-HTTPS JSON API. It cannot query a private corporate resolver, use a custom server address, request recursion-disabled authoritative answers, or inspect raw DNS packets. Split-horizon names may return no public answer even though they resolve on a VPN.

Frequently asked questions

Is this the same as dig or nslookup?

It answers common lookup questions, but it is not a complete replacement. dig can select a server, display flags and response sections, use TCP, trace delegation, test DNSSEC, and query many more record types. This page intentionally provides a narrower visual result.

Why do I see a CNAME and an address together?

A resolver response can include the alias plus records for its target. The table labels each supported answer according to its DNS type. Follow the names carefully; not every address necessarily belongs directly to the hostname you typed.

Does a low TTL make a DNS change immediate?

No. It limits how long compliant caches retain newly retrieved data. Existing caches may still hold an answer obtained under the previous, higher TTL, and application-level caches may behave differently.

Can I perform a reverse DNS lookup?

Not with this interface. It does not expose PTR queries or convert an IP address into in-addr.arpa or ip6.arpa names.

Are TXT records verified as valid SPF or DMARC?

No. The tool returns text published in DNS and performs no policy validation, include expansion, syntax audit, or mail-authentication test.