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DNS Lookup

Scan a domain on two resolvers at once and see where they disagree.

Related tools

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ASCII code converterConvert text to ASCII/Unicode code points and back.Number base converterConvert numbers between all 35 bases, exactly, with two's complement.Programming case converterConvert identifiers between camelCase, snake_case, kebab-case, PascalCase and CONSTANT_CASE, one per line. Runs of capitals split correctly: parseHTTPResponse becomes parse_http_response.Column extractorExtract a single column from delimited data (CSV, TSV…). Works on a pasted block or on a file you drop in.Delimiter converterSwap the delimiter of your data — comma, tab, semicolon, pipe or space. Drop a file in rather than pasting it — it is read in your browser and never uploaded.Extract text between delimitersPull out every piece of text that sits between a start and an end marker. Takes a whole file, so a long log does not have to go through the clipboard.Extract domainsPull the domain names out of URLs and email addresses in your text. Paste the text or drop the file; nothing leaves the page either way.Extract emailsPull every unique email address out of a block of text. Works on a pasted block or on a file you drop in.

DNS Lookup is free to use as often as you like, directly from this page. Its place is under Web & network; ASCII code converter and Number base converter answer the questions closest to this one.

How to use it

  1. Open the tool — no signup or install needed.
  2. Enter your input or adjust the available options.
  3. Get your result instantly, then copy or download it.

Frequently asked questions

What is DNS Lookup?

Scan a domain on two resolvers at once and see where they disagree.

When would I actually use this?

Checking that a domain's records really say what you just changed them to: the A record after a move, the MX records after switching mail provider, the TXT record a service asked you to add to prove you own the name.

What is the most common mistake?

Reading one lookup as the answer everyone gets. A record you changed minutes ago stays cached by resolvers for as long as its TTL, so a stale answer here — or a fresh one your visitors are not seeing yet — is normal rather than a fault. Propagation is not a delay in the change; it is the expiry of somebody else's copy.

What else is filed next to it?

ASCII code converter, Number base converter and Programming case converter share its section. They are not variants of it — being filed together is not the same as being alike — but that is where to look if this turned out not to be the tool you wanted.

Where do the figures come from?

Unlike almost everything else on this site, this tool does not run in your browser: the domain you type is sent to our server, which asks a public resolver and returns the answer unchanged. Nothing is inferred and nothing is stored. What you see is what that one resolver held at that moment — another resolver, in another country, may still hold the previous value.

Further reading

All guides →
ExplainerExtracting Every Email Address or URL from a Block of TextA URL at the end of a sentence keeps the full stop; an email address at the end of the same sentence does not. An accented first name in an address comes back truncated. Every case here was run through the tools and the exact output is reported.ExplainerSemicolon, Tab, Pipe: Choosing a Delimiter That Survives the TripWhy the reader's language decides the delimiter, what the converter does to the quoting when you switch, what the sep= first line really is, and the count of quoted cells on the same export written five ways.ComparisoncamelCase, snake_case, kebab-case: Which One, and Why You Rarely Get to ChooseThe conventions are not taste. A hyphen is the minus operator, so kebab-case cannot be an identifier in most languages - which is exactly why CSS and URLs use it. Plus the acronym round-trip that silently corrupts names, and the rule that fixes it.ExplainerBig O Notation for Beginners: O(1), O(n), O(n squared), and O(log n) ExplainedBig O describes how an algorithm's work grows as input grows. Here is what O(1), O(n), O(n squared), and O(log n) mean and why the difference matters.ExplainerWhat Is UTF-8 and Unicode? Code Points, Byte Encoding, and Why UTF-8 WonUnicode assigns every character a code point; UTF-8 encodes those code points in one to four bytes. Here is how it works and why it beat the alternatives.ExplainerHow Subnet Masks Work: CIDR, Network Bits, and Usable HostsUnderstand how a subnet mask splits an IP address into network and host parts, what /24 means, and how to count usable hosts.