I am going crazy here. One day everything was working fine. I turned pc off and went to sleep. Next day turn pc on and cannot access internet (from any browser). The situation is: I cannot open any webpage from browser (tried Firefox and Epiphany) and cannot receive emails in thunderbird. BUT if I run firefox from console as sudo, I can use it as usual. I can access Skype and pretty much any other network stuff (like installing software with apt-get etc.), also if I use Astrill VPN software I can access webpages even running without sudo. I haven't install any software or anything like that for several days = I have not a clue what could cause this. Just by the way, other Win PC in our home has no issue. Here is what I have tried to fix this: I have tried to restart my pc, router, modem - multiple times I have tried to change permissions to my firefox profile I have tried to completely re-install firefox and start with blank profile, thus no addons I have tried to change /etc/resolv.conf to an IP of my router (it was 127.0.1.1) I have tried to change my hostname (from tomino-NB to tominoNB) I think I might try even more stuff. None of it works. Can someone please try to help me. Thank you UPDATE 1: I have tried this: Removing resolv.conf - Didn't help Also "ping" and "dig" commands cannot resolve host UPDATE 2: I have tried to edit nameservers in resolv.conf but still no effect. I can ping router as well as I can ping outside IP. So definitely just some DNS issue. Is it possible that something is rewriting path to resolv.conf and using different file? UPDATE 3: I have just restarted PC and everything works now... resolv.conf went back to nameserver 127.0.1.1 . I have no clue what happened that it works again...