A shared network interface controller (NIC) interfaces a plurality of operating system domains as part of the load-store architecture of the operating system domains. A bus interface couples the NIC to a load-store domain bus (such as PCI-Express), using header information to associate data on the bus with an originating operating system domain. Transmit/receive logic connects the NIC to the network. Association logic allows the NIC to designate, and later lookup, which destination MAC address (on the Ethernet side) is associated with which operating system domain. Descriptor register files and Control Status Registers (CSR's) specific to an operating system domain are duplicated and made available for each domain. Several direct memory access (DMA) engines are provided to improve throughput. Packet replication logic, filters (perfect and hash) and VLAN tables are used for looping back packets originating from one operating system domains to another and other operations.