I can't connect to internet without using my VPN with Ubuntu 16.04 LTS [duplicate]

I am new to Linux. I was thinking that I had trouble with the wifi driver until I found out that I could connect to the web when I use a VPN. My Internet was working fine until today. I need to be able to connect to the web without using a VPN.

The messages I get are below:

Firefox can’t find the server at 

On the terminal:

$ uname -a
Linux MisterX 4.4.0-66-generic #87-Ubuntu SMP Fri Mar 3 15:29:05 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
$ ping google.com
ping: unknown host google.com
$ dig google.com
; <<>> DiG 9.10.3-P4-Ubuntu <<>> google.com
;; global options: +cmd
;; connection timed out; no servers could be reached
$ ping ping 216.58.208.78
PING 216.58.208.78 (216.58.208.78) 56(84) bytes of data.
64 bytes from 216.58.208.78: icmp_seq=1 ttl=48 time=230 ms
64 bytes from 216.58.208.78: icmp_seq=2 ttl=48 time=226 ms
64 bytes from 216.58.208.78: icmp_seq=3 ttl=48 time=249 ms
64 bytes from 216.58.208.78: icmp_seq=4 ttl=48 time=224 ms
^C
--- 216.58.208.78 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3002ms
rtt min/avg/max/mdev = 224.005/232.736/249.737/10.094 ms
$ dig 216.58.208.78
; <<>> DiG 9.10.3-P4-Ubuntu <<>> 216.58.208.78
;; global options: +cmd
;; connection timed out; no servers could be reached
$ sudo nano /etc/nsswitch.conf
passwd: compat
group: compat
shadow: compat
gshadow: files
hosts: files mdns4_minimal [NOTFOUND=return] dns
networks: files
protocols: db files
services: db files
ethers: db files
rpc: db files
netgroup: nis

I have tried:

$ sudo /etc/init.d/network-manager restart
[ ok ] Restarting network-manager (via systemctl): network-manager.service.

1 Answer

Finally, it works with both:

First ()

$ sudo mv /etc/resolv.conf /etc/backup.resolv.conf

Then, run ()

$ ifconfig

and see the name of your network adapter. Mine is: enp0s31f6

now run this command

$ sudo nano /etc/network/interfaces

and you should get something inside....delete everything and paste this (but change the network adapter name where enp0s31f6 is):

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
source /etc/network/interfaces.d/*
# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback
# The primary network interface
auto enp0s31f6
iface enp0s31f6 inet dhcp

save the document and reboot...

In my case I had only in /etc/network/interfaces the three lines below

# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback

I had to add on top

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
source /etc/network/interfaces.d/*

and below:

# The primary network interface
auto enp0s31f6
iface enp0s31f6 inet dhcp