If your network administrator provided you with the address of a proxy auto-configuration (PAC) file, select Automatic Proxy Configuration, then enter the address of the PAC file in the URL field. To automatically discover proxy servers, select Auto Proxy Discovery. If you want to configure your proxy server settings automatically, do one of the following: In the list, select the network service you use-for example, Ethernet or Wi-Fi. On your Mac, choose Apple menu > System Preferences, then click Network.