Unknown host yandex.ru, and programs do not receive Internet, why?

Question

ubuntu

There was a need to bring Ubuntu into a domain, for further opportunity to check how "Transparent Authentication" works, everything was done according to this instruction . On the net ads join -U supauser command , I received a response saying that I can’t find your server with AD at all. I decided to ping him, the ping answered unknown host , I decided to check on yandex.ru, the answer was the same. Having made a restart, and logging into the system, Ya.Disk and Skype refused to work, but the browser fully solves the tasks assigned to it. The net ads join -U supauser command
did not go further than the instructions. How can this problem be solved? SOLUTION: Problem resolved. The change in /etc/nsswitch.conf helped

lines

hosts:  files mdns4_minimal [NOTFOUND=return] dns mdns4

on the

hosts:  files dns mdns4_minimal [NOTFOUND=return] mdns4

Answer 1

It looks like something with the network settings. look, DNS is configured?