Shodan
shodan.io
The search engine for internet-connected devices — discover exposed servers, webcams, industrial systems, and IoT hardware visible on the public internet.
Shodan crawls the entire internet weekly, indexing banners and metadata from every reachable IP address. Security researchers and developers use it to audit their own network exposure, discover vulnerable infrastructure, and understand exactly what services their organisation has accidentally left public-facing.
Why it is useful
Most people have no idea how much hardware is openly visible on the public internet. Shodan surfaces exposed industrial control systems, unsecured webcams, unprotected databases, and home routers in seconds. It is the fastest way to understand the real attack surface of the modern internet — and to check whether your own infrastructure appears in it.