Every time we add a domain to a browser bar, or click a link, a request is generated that goes through several places before taking you to the website you want. In this process we find the DNS servers, which are very important.
DNS is the acronym for (Domain Name System) or (Domain Name System). This, roughly, serves so that we can put articagency.com or www.google.com in a browser and it ends up showing us the website we want.
DNS servers are responsible for "translating" the domain name request to the IP address of the server where the website is located and being able to take the user's request to its destination. The technical answer is more complex, but to understand it in a basic way it would be something similar.
Why are DNS Slow to Spread?
If a DNS change is ever made on a domain, that means it will point to another DNS server and it will be that server that tells it which IP address to look at and which web to display.
This change can take several hours, or even more than 24 hours in some cases.
This is because the companies that supply us with Internet (IPS) such as Movistar, Orange, etc... cache the data of all the DNS servers in the world to speed up traffic and save resources.
Why are changes taking time to show in the cache?
So, when a DNS change is made in a domain, this change is not reflected until all this data is updated in each of the Internet providers.
The time it takes for them to clear the cache to update the data will depend on the internal policy of each of these companies, as it is not something standardized.
For full propagation to all DNS servers in the world it could take up to 2 days. Although in general, they are usually propagated in a few hours.