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Breaking down a DNS hostname#

Not many people know this, even some already in IT, but a DNS hostname or address is read right-to-left, not left-to-right. We read and write it from left-to-right because that's what easiest given that English is a left-to-right language. But computers read DNS hostnames from right-to-left.

The root of the entire address is at the right side and .. Following this (going right-to-left, remember) is the Top Level Domain (TLD), academy. Now we have the second-level domain, upload, which gives us upload.academy. Finally we get the Authoritative Nameserver at upload.academy. which contains all the DNS records.

Visually this looks like this:

DNS Hiearchy DNS Hiearchy

DNS Hierarchy

Other TLDs#

Other very common, well known examples of Top Level Domains (TLDs) include com, com.au, net, edu, org, co.uk and many, many, many more. There are thousands of them and not all of them are open to the public, like edu, mil and gov.

TLDs are managed by ICANN (Internet Corporation for Assigned Names and Numbers). Here's a list of all supported and available (with restrictions) TLDs: https://data.iana.org/TLD/tlds-alpha-by-domain.txt

How many are there? About 1,486.