Solution: Ubuntu without wired or wifi internet connection

While one of the biggest conflicts with whom we can face when performing a fresh installation Ubuntu or some derivative of this, is the one when starting the system we realize that the system is not connected to the network for some reason.

If you are new to the system I invite you to review this article and you can find the solution to your problem in this, due to the large number of causes I will share with you some of the most common that are usually the focus of the problem.

One of the first problems we encounter is that sand what you have done is an update of your system to a next version from the terminal, you should start to check if you have problems with the dependencies, since these types of updates are the least recommended.

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Depending on the type of connection we have, the first thing we usually check is that the cable is plugged into both the computer and the modem, in the case of Wi-Fi what we verify is that it is turned on.

Edit the mac change randomly

Among the first steps that we must do to find the problem is to check that our connection is active, for this we must open a terminal and execute the following:

sudo nano /etc/NetworkManager/NetworkManager.conf

Due to changes in the version of Network Manager since its version 12 this added the randomization of MAC addresses for Wi-Fi. So this can be one of the causes for this we must add the following line:

[device] wifi.scan-rand-mac-address=no

We save the changes with Ctrl + O and exit with Ctrl + X

Finally, we just restart Network Manager

sudo service network-manager restart

Check that this activates your connection

I share with you this solution, since it was what happened to me since for some reason my connection is not active and this can be seen when writing on the terminal:

ifconfig

In case of having Wifi

iwconfig

Now what I did was check that the network was managed, for this on the terminal I executed the following:

sudo nano /etc/network/interfaces

Obtaining the following result:

auto lo

iface lo inet loopback

auto eth0

iface eth0 inet dhcp

Where eth0 is the name of the connection, when actually the name of my wired connection is enp2s0, then all I did was replace eth0 with enp2s0

Finally, we just reload Network Manager.

sudo /etc/init.d/networking restart

Activate and deactivate your connection

Although it seems absurd, this is also a solution, what I have not been able to understand is because Network Manager disables our connection at system startup and that is why we cannot connect to the network.

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To do this, we just have to type the following:

sudo ifdown eth0

sudo ifup eth0

Where eth0 is the name of your interface, remember that we know this with ifconfig or iwconfig in case of having wifi.

Check DNS

Another problem we may have is with DNS, our internet provider is the one who offers them to us, but There are times when the system does not take them, which is why we must reconfigure them for this we execute the following:

sudo dpkg-reconfigure resolvconf

Once this is done, we must restart our computer.

Change DNS

If the previous step did not work we can choose to change the dns for this we must edit the following file, I recommend you only comment the dns you have with a # at the beginning of the lines.

sudo nano/etc/resolv.conf

We can use some of the ones that google offers us:

# Google IPv4 nameservers

nameserver 8.8.8.8

nameserver 8.8.4.4

# Google IPv6 nameservers

nameserver 2001:4860:4860::8888

nameserver 2001:4860:4860::8844

Finally, we just save and reboot the system.

The last resort that we can have is to install the drivers for this we must look for them on the network or possibly we have a CD where they are included.

If you know of any other method that has resulted in editing a system configuration other than these, do not hesitate to share it with us.