======================================================================
Title:       The Domain Name System
Date:        2026-03-19
Tags:        box3, internet
Link:        https://spool-five.com/box3/20260319t181132--the-domain-name-system__box3/
Word Count:  688
======================================================================



#internet[1]
=>[1] https://spool-five.com/box3/20251019t150941--internet__box3/

The Domain Name System, or DNS, is a system for establishing _globally
unique_, _human-readable_ names that correspond to various types of
network resources, most commonly IP addresses.

The basic structure of a domain name is very simple, but also very
powerful. Each 'segment' of a name corresponds to a descending authority
layer. A name is 'resolved' by traversing these layers to find the target
information.

The domain name "www.example.com" contains **4** layers (one is implicit).
Reading from right to left:

1.  The first authority is the **root** of the domain name system.
    In the address "www.example.com", technically there is a "dot" at
    the very end of the address (www.example.com.), this final "dot"
    corresponds to the root server(s). The root contains all of the
    information relating to _top-level domain_ names, and by doing so
    also ensures the uniqueness of top-level names. Two-letter top-level
    names are reserved for countries and territories, while the remainder
    are classified as "generic".
2.  The next part of the name is ".com", which refers to the top-level
    domain _registry_ for ".com". The managers of the ".com" registry
    administer all domain names ending in ".com", although the actual
    registering and management of this task is often decentralised
    further to domain name _registrars_ who manage the business
    relationships with domain name _registrants_. An example of a
    registrar is GoDaddy.
3.  The next part is the domain, "example". The manager of a domain
    is a business or individual, and they also tend to own the server
    which the address of this domain relates to.
4.  Finally, we have further "subdomains", such as "www". In this
    case "www" would indicate a web directory on the "example.com"
    server, owned by a particular user/group of an operating system.
    There can be many subdomains, which all might serve different purposes
    relating to the "example.com" domain (for example "api.example.com"
    "payments.example.com").

As we can see, a short, simple domain name like "www.example.com" reflects
a large variety of parties and trust relationships within the internet
architecture:

-   root servers
-   domain name registries, domain name registrars
-   individuals or organisations who may own a particular name
-   further network locations relating to those individuals or
    organisations (or sometimes subdomains can be owned/operated by
    further parties, for example individuals who sign up for a wordpress
    domain)

That's a lot of information to pack into a short, human-readable string
of characters.

The most interesting things about the DNS are:

-   It is global and unified, whilst also being highly distributed
-   Each party in the chain only deals with their own particular
    domain, this was efficient and effective _data minimisation_ long
    before GDPR!
-   The names themselves are easily understandable and user-friendly

Finally, the other key point about the DNS is that there are governance
mechanisms to decide on policy about it at the global level. User-friendly,
human-readable names bring along their own issues, beyond the 'technical'
or engineering questions. For example, should some names, such as
sensitive religious terms, be forbidden? Do copyright holders also have
a claim over domain names? Should I be allowed to register a name that
_looks_ very similar to a legitimate business in order to try trick its
customers and steal their data?

In order to address some of these _policy_ matters, ICANN, the Internet
Corporation for Assigned Names and Numbers, exists. It adopts a
_multistakeholder_ model of governance, where many stakeholder groups
make decisions and policy about the global name system in a collaborative
and open manner.

I think in today's world, we sometimes take for grated how valuable and
impactful the _global_ aspect of the internet has been. It could have
easily been otherwise. Part of what ensures this global, interoperable
underlying architecture is the DNS.

The DNS is already very old (almost 43 years!). There have been lots of
other attempts to develop alternative naming systems, using blockchain,
DIDs, etc. Yet, nothing yet has managed to produce a solutions that is
as effective and scalable as the DNS; a great engineering achievement
of the 20th century!