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DNS: what they are, how they work and how they block unwanted content

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If Internet use was already high in the pre-pandemic period, during and after confinement, users of this network spend an average of 6 hours and 54 minutes online (3 hours and 39 minutes in the case of smartphones). Teleworking, changing consumer habits and social relations justify this upward trend.

As stated in an article published by Marketing4ecommerce (in spanish), the number of internet users grow 7.4% worldwide and reach 4.660 millions users. Many of these users are minors and teenagers, who are increasingly connected to the virtual environment. Given this reality, it is essential for adults to be alert to the content consumed by children.

Currently these minors and teenagers find it difficult to surf the Internet without encountering the large amount of adult content circulating on the web. To block them there are tools included in our antivirus and other security solutions; in this article we will focus on DNS.

What is a DNS?

DNS, or Domain Name System, is a system whose main function is to “translate” the domain names we are used to, such as emiralfg.com, into binary identifiers associated with the computers connected to the network or IP addresses, such as

DNS server

Internet providers have a series of computers called DNS servers that are responsible for translating domain names into the IP address of the page, so that we can access the domain without having to know the IP address of the computer where it is hosted.

Alternative servers vs. DNS of the operators

Among the advantages we find in alternative DNS servers (Google, Clouflare, OpenDNS, etc), we have:

  • Reliability: increased availability.
  • Speed: is usually found above the DNS of the operators..
  • Security: some offer phishing protection or DNSSEC support.
  • Parental Control: some offer the possibility of filtering access to pages not recommended for minors.

We can also compare the free DNS from those that are paid:

  • Free DNSs tend to have fewer features than paid DNSs.
  • Paid DNS will usually be more secure and perform better..
  • Paid DNS will offer us many more customization options.

There are two other types of DNS, public and private:

  • The public ones are those that are served to the whole world and come from an Internet service provider or a dedicated one..
  • Private DNS are those that are used in the private sector, i.e. in companies.

How to change the DNS

Once we have made the comparison (we know which are the best DNS on the market, the ones that work best for our connection and the ones that offer us all the advantages we are looking for) it is time to change them. This can be done at the router level, so that all the connected equipment remains under the restrictions and benefits of the DNS, or at the individual level in each of the devices.

At the individual level

  • First, we must click on the “Start” button. From there, we open the “control panel”.

panel de control seguridad dns

In the control panel, access the “networks and internet” option.

redes internet dns

Next, we access the “network and shared resources center”, as shown in the following image:

centros de redes dns seguridad

Now it is time to click on “change adapter configuration”:

cambiar configuracion dns

On the one hand, we have the Ethernet connection. If it is ours, we must click on “local area connection” with right click and then on the “properties” option.

configuracion adaptador

The next step is to click on Internet Protocol version 4 (TCP/IPv4), Properties.


protocolo versin 4

We added a DNS that blockspornographic content. We have found these DNS on the page (in spanish): https://www.clasesordenador.com/como-bloquear-sitios-web-para-adultos-en-windows-10/

internet protocolo version 4

We open cmd and check that the DNS are configured:



For the changes to take effect, it is necessary to restart the computer.

reiniciar el equipo

Checking DNS modification to prevent access to inappropriate content. We try to open a page with sexual content and it does not allow it. There are plenty of DNS that allow to block sexual content, gambling content, violence, hatred, discrimination, etc.…

busqueda web

In router

Not all routers will allow us to change DNS, due to their internal configuration, so we would have to change them manually in our computer.

The first step is to open the router configuration from our browser to the gateway (if we do not know the IP of our router we can open a MS-Dos window and do an ipconfig.


The “gateway” section will be the IP of the router:

ip router dns

Before logging in you must enter the user and password of your router, the most used by default are:

  • 1234/1234
  • Admin/
  • /admin

We must look for the DHCP server configuration section, as this should be the one that includes the DNS. This section can be included in “LAN settings” or in basic configuration.

If it does not allow us to change the DNS manually, since each router has its own particularities, we will have to do it individually for each computer device.

It must be taken into account that we cannot completely block unwanted content, but we can apply some measures, we just have to dedicate a little time to it.



Área tecnología





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