Subdomain Finder
Discover active subdomains for any domain by checking 35+ common subdomain names.
How to use the Subdomain Finder
Discover active subdomains for any domain by checking 35+ common subdomain names. Enter the domain, hostname, IP address, selector, or record value requested by the tool, then run the check to see the current public configuration. Use the result to confirm whether the domain is resolving correctly, whether email authentication is aligned, or whether a visible trust issue needs follow-up.
Enter the domain or value you want to inspect.
Review the returned records, warnings, and status signals.
Fix the DNS, hosting, SSL, or email setting, then retest.
What to check next
A single lookup rarely tells the whole story. For production websites, verify DNS, SSL, email authentication, blacklist status, and public security headers together before making a launch, migration, or deliverability decision. Common next checks after this page include DNS Checker, WHOIS Lookup, Port Scanner.
Subdomain Finder FAQ
What does the Subdomain Finder check?
Discover active subdomains for any domain by checking 35+ common subdomain names.
Is the Subdomain Finder free to use?
Yes. The basic subdomain finder is free and does not require a login. Paid Hostao reports and fix plans are available when you need analyst review or managed remediation.
When should I run the Subdomain Finder?
Run it before DNS changes, email sender changes, hosting migration, SSL renewal, launch checks, or whenever a website, domain, or email delivery issue needs quick verification.