What is IP Address?
IP stands for Internet protocol, Its a unique address of your computer when you are on internet.
If you are visiting a website. that website is hosted somewhere on another computer
How do you find that website? Its through the IP address of that computer.
You type www.something.com
but that is then translated to the IP address by DNS server.
How does an IP address look like?
192.168.0.1
When someone wants to visit your home. He looks for your Home address, but on internet
when you want to find someone, you look for their IP address.
There are about 2 billion IP addresses at the moment.
looks like big number right? Not very big..
If you want to scan all the IP addresses, and you want to know how many of those IP address are Hosting websites
you can do so by Scanning all those IP addresses for Port 80
HTTP service runs on port 80 of your computer. if you want to turn your computer into a Web server
you can do so by installing apache server on your computer. :) anyways
There are lets say 2 billion IP addresses, right? scanning them would be difficult?
not very much..
1 GB internet connection can scan about 1 million IP addresses / second
so ? it will take few hours. depending upon your internet connection.
and you will be able to know. how many Computers in the World are web servers by scanning port 80
How to scan the Whole Internet
Its very simple :) actually
on your linux machine, open your terminal
nmap -A -Pn 0.0.0.0/0
It will start scanning all the internet for you, on most IP address it will fail because no one is using them.
but on those IP addresses which are on internet and being used by some service they will return a response.
and that will confirm you that this IP is alive and is being used by someone.
you can request a web page from that IP address by typing this
curl 172.101.25.13
if that is a web server, it will return you a web page :)
that's how internet browsing works. I hope you learned something.
if you want to find all the computer which are running a Steem Node?? what you will do??
you will scan for port 8090
