What does Subdomain Lookup do that other Network pages on this site do not?

Subdomain discovery needs network lookups. Not reliable in-browser. Stopped. Short version: Needs DNS/CT probes — stopped this wave.

Does Subdomain Lookup upload my file or text to Tool-You servers?

No. Subdomain Lookup runs in this browser tab. Files stay on the device. Limit note: Needs DNS/CT lookups. Stopped this wave.

Should I use WHOIS Lookup instead of Subdomain Lookup?

Use Subdomain Lookup when you need Needs DNS/CT probes — stopped this wave. Use WHOIS Lookup when you need Stopped — no fake download. They share a category (Network) but not the same job.

What are the limits of Subdomain Lookup?

Needs DNS/CT lookups. Stopped this wave. Also: Subdomain discovery needs network lookups. Not reliable in-browser. Stopped.

Subdomain Lookup

Needs DNS/CT probes — stopped this wave.

Subdomain discovery needs network lookups. Not reliable in-browser. Stopped.

What Subdomain Lookup does

Subdomain discovery needs network lookups. Not reliable in-browser. Stopped.

The interactive controls for Subdomain Lookup load after this article so crawlers still read the instructions. Path /network/subdomain-lookup is the canonical address. Work happens on this device; Tool-You does not take a copy of the file or pasted text for Subdomain Lookup.

How to use Subdomain Lookup

Keep this tab on Subdomain Lookup (/network/subdomain-lookup). Pasting into the wrong Network tool (for example WHOIS Lookup) changes the job.
Paste or type the input Subdomain Lookup expects. Path hint: network · subdomain lookup. Needs DNS/CT probes — stopped this wave.
Apply the Subdomain Lookup action only. Parse URL is a different transform (Split a URL into host, path, query, and more.). Subdomain discovery needs network lookups. Not reliable in-browser. Stopped.
Copy the output of Subdomain Lookup if you need it elsewhere. Size/complexity still follows: Needs DNS/CT lookups. Stopped this wave.
If the text job is actually Stopped — no fake download., leave Subdomain Lookup and open WHOIS Lookup.

When not to use Subdomain Lookup

Skip Subdomain Lookup when a neighbor tool matches better — start with WHOIS Lookup or Parse URL — or when the description already warns the job will fail. In the tool’s own words: Subdomain discovery needs network lookups. Not reliable in-browser. Stopped.

Questions about Subdomain Lookup

What does Subdomain Lookup do that other Network pages on this site do not?: Subdomain discovery needs network lookups. Not reliable in-browser. Stopped. Short version: Needs DNS/CT probes — stopped this wave.
Does Subdomain Lookup upload my file or text to Tool-You servers?: No. Subdomain Lookup runs in this browser tab. Files stay on the device. Limit note: Needs DNS/CT lookups. Stopped this wave.
Should I use WHOIS Lookup instead of Subdomain Lookup?: Use Subdomain Lookup when you need Needs DNS/CT probes — stopped this wave. Use WHOIS Lookup when you need Stopped — no fake download. They share a category (Network) but not the same job.
What are the limits of Subdomain Lookup?: Needs DNS/CT lookups. Stopped this wave. Also: Subdomain discovery needs network lookups. Not reliable in-browser. Stopped.