How the Domain Name System Works

if you own or want to own a domain name,  you must understand how the Domain Name System works, including the purpose, rules, and limitations of TLDs, or Top Level Domains. Below I will dive into how internet routing works by utilizing IP Addresses and how IP addresses are assigned.  I will also outline the parts of a URL, and how your URL impacts internet routing.  I really dive deep into TLDs, including the types of TLDs and their origins and purpose.  In the 1960’s the Advanced Research Projects Agency (ARPA) designated the first ever TLD (.arpa) while designing a network the US Government could use to send information between entities.  The work they did would later result in the internet protocol and routing, as well as the Domain Name System of the internet we know today.

How Internet Routing Works with dns

To reach another person from one computer to another you have to have an Internet Protocol (IP) Address.  The internet routes all traffic numerically with Internet Protocol (IP) addresses assigned to each computer on the internet, for example if you enter into your browser, it will take you to  This is because the IP is the IP that redirects to the friendly name  Domain Registrars assign IPs to specific domain names, but more on that later.  The IP addresses work great if machines are communicating with one another, but if humans are trying to brows the web remembering IP addresses would make things difficult.

To solve this issue the Domain Name System (DNS) was established to make the browsing internet human useable.  In 1998 a not-for-profit organization ICANN (Internet Corporation for Assigned Names and Numbers) was established.  the Internet Assigned Numbers Authority (IANA) is a department of ICANN and manages and creates rules around domain namesA Registry is an organization who is given authority by IANA to set and enforce rules around a specific TLD.  Domain Registrars are delegated commercial sales of domain names.  Before ICANN there were nearly no rules governing domain names.

Domain Name System Hierarchy

How URLS Work

Now that you have the basics of how the internet works, let’s take a look at how a URL works.  Like your street address, directions to a URL is determined right to left.  For example, Let’s say you wanted to pickup a pizza from Pizza Hut.  You would google their street address which might be something like:

123 Maple Street
Buffalo, NY 14201

How would you know where this address is?  You probably would NOT arrive at your location easily by following a route to the address left to right or top to bottom – you would not begin your search by looking at every street address containing “123” or go to every single Maple Street in the world.  Of course, we know we would first go to the state of New York, city of Buffalo, then locate Maple Street, then locate number 123.  This is so common we don’t think about it.

URLs work similarly to street addresses, read them right to left.  Each TLD is on a separate network (different range of IPs) – so when you enter in your browser, the network knows to send the traffic to the .com network, which will then route you to google website.


Types of Top Level Domains

As a domain investor, you will here TLDs classified in terms shown below:

  • gTLD or Generic TLDs are the largest group of TLDs and account for most of the newly available domains, ranging from .aaa to .zone, including .com.
  • ccTLD or Country Code TLDs represent specific geographic locations such as .us (United States TLD) or .de (Germany TLD).
  • IDN ccTLD – internationalized country code top-level domains such as
  • Infrastructure TLD, such as .arpa is used for technical purposes and now stands for Address and Routing Parameter Area. For historical reasons, the .arpa domain is sometimes considered a generic top-level domain.
  • Historical TLD are TLDs that are no longer in use and removed from the DNS root zone making them undiscoverable, for entities or countries that no longer exist, such as .yu for Yugoslavia.

Purpose for Each TLD

Each TLD is operated with different rules and by different entities, but let’s start form the beginning.  In the 1960s, ARPA established the first TLD .arpa.  – these are the current rules for those TLDS:

A TLD is most often sponsored by a registry.  To get a TLD, a perspective registry needs to submit a detailed application and fee (likely around $200,000) to ICANN. ICANN will evaluate the application to determine if it will issue the TLD and to which registry (often there are competing registries for TLDs) – so filling out the paperwork and paying the fee does not guarantee the registry will be awarded the TLD.

Below is a list of TLDs that were introduced, and In the 1980s Seven Generic TLD’s (gTLD) were established – .com, .org, .gov, .int, .mil, .net and .edu – below is a list that contains their current registry and sponsor, as this has changed over time.

.govlimited to United States governmental entities and agencies as well as qualifying state, county and local municipal government agencies.1980s
.miluse by the United States military.1980s
.eduThe .edu TLD is limited to specific higher educational institutions1980s (operated by verisign)
.intIs strictly limited to organizations, offices, and programs endorsed by a treaty between two or more nations.

In between the years 2001 and 2003, several new gTLDs.

TLDPurposeYear EstablishedRegistry
.bizregistrations may be challenged later if they are not held by commercial entities in accordance with the domain's charter2001
.nameany person or entity is permitted to register; however, registrations may be challenged later if they are not by individuals2001
.aeroMust verify eligibility for registration; only those in various categories of air-travel-related entities may register. 2002
.musuemMust be verified as a legitimate museum2002
.asiaofficial designated regional web address for Asia2003
.catserve the needs of the Catalan language and cultural community on the Internet2003

As of 2019, there are now more than 1000 TLDs, you can find a full list with information about each TLD here on Wikipedia.

Parts of a URL – uri, urn, URC, DATA URi, resource and access method

Lastly, as a Domain Investor I think you should understand how a domain name fits into the routing and architecture of a URL.

Parts of a URL - URI and URL

Uniform Resource Identifier (URI)

A URI is a string of characters used to identify a name or a resource on the Internet such as http, https and ftp.  A URI identifies a resource either by location, name, or both.  A URI has two specializations known as URL and URN. A URI can be a URL, but a URL cannot be a URI. An example of a URI is:

Uniform Resource Locator (URL)

A URL specifies where an identified resource is available and the mechanism for retrieving it.  A URL defines how the resource can be obtained. It does not have to be HTTP URL (http://), a URL can also be (ftp://) or (smb://).  Example of a URL:

Uniform Resource Name (URN)

A URN Identifies a resource by a unique and persistent name, but doesn’t necessarily tell you how to locate it on the internet. Both URNs (names) and URLs (locators) are URIs, and a particular URI may be both a name and a locator at the same time.  Examples of URN are:

  • urn:isbn:0451450523 to identify a book by its ISBN number.
  • urn:uuid:6e8bc430-9c3a-11d9-9669-0800200c9a66 a globally unique identifier
  • urn:publishing:book – An XML namespace that identifies the document as a type of book

Uniform Resource Citation (URC)

A URC points to meta data about a document rather than to the document itself. An example of a URC is one that points to the HTML source code of a page like. An example is:

Data URI

A Data URI is when data can be placed directly into a URI. An example would be:

  • data:,Hello%20World.


I hope what you learned about the domain name system in this article will allow you to understand where your domain name fits into the Internet. For further reading about DNS and Domain Name, you can view my 10 part series about the most popular DNS Records, If you’re looking to buy a domain, you can view 14 Things You Must Know Before You Buy A Domain Name.  If you received some added value from my post, please like and follow us on FacebookTwitter, and LinkedIn, or subscibe to

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