IP addresses and DNS


#1

A student asked this question, and I thought it was a good one. Why can’t one type the numerical IP address into a URL and get to the same address, say, as code.org, rather than simply typing in “code.org”?


#2

With the caveat that I’m on the fringe of my knowledge here…

You can. But it’s tricky these days because of how domain names often redirect to other servers in the cloud etc. There are a lot of redirects involved managed by DNS systems. Going to an IP address directly may not be the IP address of a web server that can give back meaningful results in the browser. That’s why it doesn’t work for code.org. Alas, it used to be much more straightforward.

However I found this one for google works: http://172.217.6.206


#3

It used to be common that an IP address was dedicated to one website. But due to a shortage of IP addresses available with IPv4, developers came up with creative solutions for hosting multiple websites on a single IP address. Now days many web servers and cloud services to require a domain name in the request so that they know exactly where to send the request.