> Ok, allow me to be more precise. The loopback _link_, the virtual cable, the virtual interface thingy has zero packet loss. If you imagine a wire that represe

> Ok, allow me to be more precise. The loopback _link_, the virtual cable, the virtual interface thingy has zero packet loss. If you imagine a wire that represents loopback, it will never congest, never have interference, never have any loss. > The packets will _always_ reach the other end. Now, what happens after they reach the other end, that's a separate story. The article indeed showed that it's possible that the kernel network stack dropped packets because of full buffers, or the CLOSE-WAIT thing. Which is kind of ironic, because that's how packets get lost in the wild as well. The router's buffer gets full due to congestion and it drops them.