Dear Tecnogalaxy readers, you may have heard about DNS several times, but have you ever wondered what it is, how it works and why it is used? Today we will see in detail its operation and the importance of this service.

Domain Name System, in computer science and telecommunications, means a system used to assign names to network nodes.

Domain Name System (DNS) translates a domain name into an IP number (called direct resolution) and vice versa from an IP number to a domain name (called reverse resolution).

A simple example that we use every day is when you open your browser and type in the address of google, this address corresponds to an IP address.

Each site corresponds to an IP and as you can imagine it would be unthinkable for a human to remember the IP addresses compared to a name, It is right here that DNS comes to help us by solving the name of the site in an IP address.

Computers don’t understand names because they use numbers, every networked computer has an IP address as we know, which is a set of numbers, or a set of numbers and letters in the case of the new IPv6 addresses.

We humans do not go (generally) very well with numbers, if we have to memorize strings like these for example:

If you think the same thing happens with telephone numbers, for this reason there are telephone directories, Name-Surname and tel number.

DNS, Domain Name System, is nothing more than a directory, when you enter the name of an internet domain in your browser the domain name is converted to an IP address so you can contact the server and show the content of the web page you want to visit.


There are different types of DNS records, and different types of information can be matched to each.

The main ones are:

Record A – Indicates the correspondence between a name and one (or more) IP addresses (for the accuracy IPv4 addresses, that is the version currently in use).

Record MX – (Mail exchange) indicates to which servers email should be sent for a certain domain.

CNAME records – They are used to create an alias, that is, to make the same computer known with multiple names. One of the uses of this type of record is to give a host that offers multiple services a name for each service. In this way, the services can then be moved to other hosts without having to reconfigure the clients, but only by changing the DNS.

PTR record – DNS is also used to realize reverse resolution, that is, to match the corresponding domain name to an IP address. For this, “PTR” records are used (and a specific area of the namespace).

AAAA record – It is like Record A but works with IPv6 and returns an IPv6 address.

SRV records – Identify the server for a particular service within a domain. They can be considered a generalization of MX records.

TXT record – Associate arbitrary text fields to a domain. These fields may contain an informative description or be used to create services.

There are also types of “service” records, necessary for the operation of the distributed database:

NS Records – Used to indicate which are the authoritative DNS servers for a certain domain, or to delegate the management.

Record SOA – (Start of Authority) used for DNS zone management.

Let’s take as an example the Registration or the Transfer of a Domain, as soon as new IPs are inserted and DNS are modified, the procedure of DNS Propagation begins, a period that lasts about 2 to 12 hours during which your site may not be displayed correctly and be unreachable.


We can verify the correct propagation of the DNS of your site and possibly check if there are malfunctions, through some Tools available Online.

ViewDNS.Info (https:/// one of the best and the easiest to use for Dns Propagation. Just log in to the website, enter the domain name and he will look for the state of DNS propagation in 19 servers, showing the result of the IP of the server from which he got result. (https:/// offers monitoring from many nodes around the world. To check if the site is active and accessible just check the server ip and if it is not the same IP of your server, then it is not completely propagated. (https:/// is definitely the most used, even here just type your domain name to run the test and any problems found will be highlighted. (https:/// allows a DNS lookup to verify the IP address, hostnames and other DNS information against a random selection of servers worldwide, useful to check the current state of DNS propagation after changing domain zones. (https:/// offers many Diagnostic Tools, including Check DNS Domain.

Another online portal with different tools is, available at the following link (

As always make good use of it by making tests on your devices / computers , making them on devices/ computers is illegal.

To the next article!

N.B.: I do not assume any responsibility for the use that you will make of the guide, as drawn up for educational and educational use.

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