Summary: Why use loopback interfaces? Learn the details in this Cisco CCNA tutorial from Chris Bryant, CCIE #12933. Keywords: cisco, ccna, certification, exam, pass, how, loopback, interface, 127.0.0.1, ping, pc, reserved Article Body: As a CCNA candidate, you most likely have some background in PC hardware and workstation support. If so, you're already familiar with loopback interfaces,...