Give a computer set up the network, convenient management, multiple devices connected to the exchange of fool no fool the exchange of access to the wall outlet, configure the IP, the command prompt ipconfig is under 169.254 segment address, trying to identify a network cable no problem, the adapter is to install, so also no problem, IP is no conflict, no one is ready, and finally try to cable directly to a wall, find IP configuration is successful, can connect to the Internet, why is this?