What´s so important about DNS?

Without the DNS protocol, we would be lost

The DNS (Domain Name System) is a system based on a decentralized system of hierarchical naming protocol, which aims to associate the domains of websites to their IP addresses.

Remembering the IP address of a website would be complicated, but if we had to remember multiple IPs to access different websites it would be virtually impossible. An IP address is a numeric address, it would be something like this: 216.58.210.163. To make this task easier, the DNS protocol, what it does is it translates these IP addresses to domain names, for example, google.com, register.es, were created etc.

In addition, it would be further complicated if the numerical address would variate, which is something that could happen for various reasons, without the domain doing it, through a process called "name resolution". It is also used on the contrary as "reverse name resolution", through which, using an IP address, you could know the domain name, and also use for resolving mail servers where a domain name like Hotmail.com, we can obtain the server that should be used for e-mail delivery.

In summary, to save time when it comes to internet browsing, the DNS protocol

Some basic digital terms to know:

- Host Name: is the host name in one word, such as www, blog, etc.

- FQHN (Fully Qualified Host Name): is the full name of a host: www.register.es

- TLD (Top Level Domains): are the top-level domains, such as .com, .org, .net, .co.uk, etc.

DNS Structure

The DNS system is structured like a tree, may the main TLD server, also called root server, delegate authority to its sub-areas. This is how a domain in its lower levels specializes

(.es===>register.es)

(.es===>.gob.es===>administracion.gob.es)

Way the DNS system operates

1- A DNS customer program running on the PC of a user and generates requests to a DNS name server (we type www.register.es but our browser must know which IP address belongs to that domain)

2- DNS servers are those that resolve customer's request performing the search by the aforementioned tree structure, it will at increasingly lower levels until it finds the requested response, which is returned to the customer.

Cache

At the same time that a name server responds to the request of a customer, it also sends the validity period of the same or TLL (time to live), said response being filed in the cache. Thus, if the user wanted to re-access a domain that has already visited before, the DNS service will be stored information from the previous visit in the cache and thus will provide access, it will be a more efficient access.

Domains Domains DNS DNS TLD TLD DNS System DNS System DomainNameSystem DomainNameSystem DNS Protocol DNS Protocol IPs IPs DNS Structure DNS Structure Cache Cache