A virtual computer system including multiple virtual machines (VMs) is implemented in a single physical computer system. The multiple VMs have their own layer 2 and layer 3 addresses, but they share a common network connection for which only a single layer 2 address may be used, such as in the case of a standard wireless network interface card (NIC) or in the case of multiple NICs and a standard NIC teaming solution. For outgoing data frames from a VM to a network entity outside the virtual computer system, the layer 2 address of the VM contained in the source address field is generally replaced with the layer 2 address of the network connection. For incoming data frames from a network entity to a VM, the layer 2 address of the network connection contained in the destination address field is generally replaced with the layer 2 address of the VM.