Free subdomain finder
Discover the subdomains attached to your domain — including the forgotten ones that become entry points.
Free · no account · instant.
What it checks
We combine public sources and active resolution to find subdomains your inventory may have missed.
We show which subdomains actually resolve and respond — the ones that matter.
Dangling records pointing at unclaimed services are flagged for subdomain-takeover risk.
For each live subdomain we surface the open ports and services it exposes.
Frequently asked
It enumerates subdomains using public intelligence and active DNS resolution, then verifies which are live and what they expose.
Forgotten subdomains are a top entry point for attackers. Finding them is the first step to reducing your attack surface.
Yes — no account required. Subdomain discovery is part of the free attack surface scan.
Want this continuously, not once?
The free tool is a snapshot. SICenter monitors your whole estate and alerts you the moment something changes.
Start monitoring free