Shodan is the world's first search engine for Internet-connected devices. ... Use Shodan to discover which of your devices are connected to the Internet.
Shodan is a search engine that lets the user find specific types of computers (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. 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 at the moment (HTTP port 80), but there is also some data from FTP (21), SSH (22)Telnet (23), SNMP (161) and SIP (5060) services.
IOT search engine:
https://en.wikipedia.org/wiki/Shodan_(website)
https://www.shodan.io/explore/popular
related: