www.shodan.io: not crawl the page, just crawling equipment
Common filter:
net
city
country(CN/us)
port(80/21/22/23)
the
hostname (host or domain name)
server
============================================
google search syntax
googlehacking
exploit-db.com/google-dorks
User Info
Mail / Host
Thehrvester
metagoofil
Russian search engine ---
www.yandex.com
=======================================
maltego