What is DNS?

When you type a URL into your browser's address bar, that is the first step in your browser knowing where to look online for the page it's supposed to load:

But with that URL, the browser still needs to figure out what server it is connecting to get the webpage. In the example above, just "https://routethis.com" doesn't by itself give enough information. That's where DNS (Domain Name System) comes into play.

DNS is going to allow our browser to translate that URL, or "domain" into the IP address of the server that our browser should actually go lookup. The browser will go to a known "DNS Server", such as Google's 8.8.8.8 IP, Cloudflare's 1.1.1.1, or maybe even another DNS owned by a customer's ISP (which might be the company you work for!).

That DNS server will translate the friendly, plain-text URL (routethis.com) into the specific server IP address (34.195.202.82 for RouteThis at the time of writing) that the browser needs to actually go get information from to load a page.

This same concept applies to URL requests that are not for a browser. It could be phone apps requesting the URL they need to function or a smart device looking for information it needs to talk to its servers. 

Customers sometimes set up firewalls, VPNs, or parental controls that will cause DNS lookups to fail or to return the wrong information. Think of it like a wrong mapping, the browser requests "routethis.com" but it gives the wrong IP, so unexpected information returns. This would cause a RouteThis "DNS lookup" to fail!