This procedure is only with cable, not for wifi
First check that your interface is up with the command “sudo ifconfig” :
You may not have an IP Adress automatically like in this screenshot. If it’s the case, simply type “sudo dhclient eth1” to get one with DHCP.
If it doesn’t work, try to directly ping an IP address like google’s dns server 22.214.171.124 with the command “ping 126.96.36.199“. If it works, you probably have a nameserver problem. Simply add the line “nameserver 188.8.131.52” in /etc/resolv.conf