I can't connect to internet without starting some programs

[fabri94]

I just installed XUbuntu 17.04, for using it as a little home theater/kodi etc.. But I have a little problem!
I can't acces to internet if I don't start Mozilla Firefox! Wifi is connected, so I can even ssh to this pc, but for example I can't ping from the local console to google, and some other programs, like Kodi, can't access internet! But if I start a search via Mozilla, everything start working!
What should I do?

Thanks for your help

[giulux]

La lingua del forum è l'italiano.
Modifica il post.
Grazie.