Shodan is a search engine that lets the user find specific types of computers (web cams, routers, servers, etc.) connected to the internet using a variety of filters. Some have also described it as a search engine of service banners, which are meta-data the server sends back to the client.^[1] This can be information about the server software, what options the service supports, a welcome message or anything else that the client can find out before interacting with the server.

Shodan collects data mostly on web servers (HTTP/HTTPS - port 80, 8080, 443, 8443), as well as FTP (port 21), SSH (port 22), Telnet (port 23), SNMP (port 161), SIP (port 5060),^[2] and Real Time Streaming Protocol (RTSP, port 554). The latter can be used to access webcams and their video stream.^[3]

It was launched in 2009 by computer programmer John Matherly, who, in 2003,^[4]

shadon search engine