Hostname Where Change on QB?

Hey, again me :)

My question now is where I change hostname for QB? I can't change in /etc/hostname on Ubuntu (if I change hostname restore back on default hostname which my PC). I want change hostname for QB because when I install it I use ENTER for default and QB give me "proto" hostname. I check on Win and Ubuntu it's same hostname (OK), why QB give me "proto". :)

Thank you for answer.