Cheat Sheet: What is a “DNS” and why should I care?

For people who remember phone books, the DNS ( Domain Name System is the phonebook of the Internet. You just can’t use it to help a little child get his head higher than the dinner table.

Humans access information online through domain names, like www.cyberprotection-magazine.com. DNS translates domain names to IP addresses so browsers can load Internet resources. Every device, from smartwatches to servers, has a unique IP address that connects one device to another. DNS servers eliminate the need for humans to memorize IP addresses.

The process of DNS resolution involves converting a hostname (such as www.example.com) into a computer-friendly IP address (such as 192.168.1.1). Every device has one and cannot connect to the internet without one. When a user wants to load a webpage, the DNS in use can translate what a user types into their web browser and the machine-friendly address necessary to locate the example.com webpage.

Different DNSes

In order to understand the process behind the DNS resolution, it’s important to learn about the different hardware components a DNS query must pass between. For the web browser, the DNS lookup occurs “behind the scenes” and requires no interaction from the user’s computer apart from the initial request.
There are 4 DNS servers involved in loading a webpage:

• The DNS recursor is like a librarian searching for a particular book somewhere in a library. The DNS precursor is a server designed to receive queries from client machines through applications such as web browsers. Typically the recursor is then responsible for making additional requests in order to satisfy the client’s DNS query.
• The root nameserver is the first step in translating (resolving) human-readable host names into IP addresses. It serves as a reference to other more specific locations.
• The top-level domain server (TLD) hosts the last portion of a hostname (In example.com, the TLD server is “com”).
• The authoritative nameserver is the last stop in the nameserver query. When the authoritative name server accesses the requested record, it returns the IP address for the requested hostname back to the DNS Recursor (the librarian) that made the initial request.

Why you need to know this

Human error is at the root of more than 90 percent of cyber breaches. It usually happens when someone clicks on a malicious link in an email, text, or social media. No one has time to look up every IP address before you clicking just to see if it is malicious. But we talked with Quad9 about their totally free… yes, we said totally free, DNS that blocks millions of malicious sites. Find out how by checking out the interview on Crucial Tech.