After moved the torrent daemon on the NAS, the Raspberry Pi was lost. So, I thought about an simple equation: usb printer + Raspberry Pi = network printer. Easy. Obviously, thanks to CUPS.
I followed this tutorial, but I found an issue. Both PC with Fedora and PC with Ubuntu saw the printer and connected to it, but I was unable to print also a small sheet. After many attempts, I found a solution: the key is to use an opensource HL-1650 .ppd file. So to make the Brother HL-2030 (but also a Brother HL-2040) working as a network printer through a Raspberry Pi, download this BRHL1620.ppd file or the more complete BRHL2030-HL1250.ppd and use it during the CUPS printer installation.