Out-of-band management system and method

The invention provides an out-of-band management system and method. The out-of-band management system comprises a mainboard management controller, a network interface card, a central processing unit and at least one expansion component, the mainboard management controller obtains a media access control address value of each device in each extension component through the central processing unit, and generates a first Ethernet frame according to the media access control address value of each device, an out-of-band management instruction corresponding to each device and the media access control address value of the mainboard management controller; sending the first Ethernet frame to a network interface card; the network interface card determines a to-be-managed device and a target out-of-band management instruction corresponding to the to-be-managed device in the plurality of devices according to the first Ethernet frame, and routes the target out-of-band management instruction to the to-be-managed device, a mul