I've updated my kernel recently and that got Ethernet support all messed up (meaning: the hardware was saw by the system, but I couldn't connect to any network). I fixed that by including the parameters on /etc/network/interfaces:
auto enp3s0 iface enp3s0 inet dhcp
That got the Ethernet working again after a reboot.
I'm willing to bet that I have to inform some config file about the enp3s0 being my Ethernet port, but I don't have any idea which file would that be.
If anyone has an idea, it'd be very appreciated.