A host computer is linked to a network interface controller having a plurality of network ports connectable to a data network. The network interface controller has an embedded central processing unit, a host interface linked to the host central processing unit, a sideband interface and a baseboard management controller linked to the network interface controller via the sideband interface. The baseboard management controller connects to a management network via the management network port. The embedded central processing unit in the network interface controller is linked to a datacenter manager via the management network port of the baseboard management controller, enabling the datacenter manager to instruct the embedded central processing unit to control data flows in the network interface controller between the host interface and the data network.