In a computing system, sharing a physical NIC device among multiple virtual machines may be implemented by a customer virtual machine by receiving, by a virtual network interface card (NIC) driver of a customer operating system (OS) running in the customer virtual machine on a computing system, a customer OS request packet for transmission by a physical NIC driver over a network coupled to the computing system, and copying at least a portion of the customer OS request packet into a free block of shared memory of the computing system and appending the block to a transmission queue in the shared memory. Next, a service virtual machine may support the implementation by fetching the block from the transmission queue by a virtual NIC driver of a service OS running in a service virtual machine and packaging the portion into a service OS request packet, passing the service OS request packet to a service OS network stack component of the service OS, routing the service OS request packet, by a bridge driver of the service OS network stack component, to the physical NIC driver, and sending the service OS request packet over the network by the physical NIC driver.