Secure networking processes, such as packet encapsulation and decapsulation, can be executed upstream of a user or guest operating system provisioned on a host machine, where the user has substantially full access to that machine. The processing can be performed on a device such as a network interface card (NIC), which can have a separate network port for communicating with mapping systems or other devices across a cloud or secure network. A virtual image of the NIC can be provided to the user such that the user can still utilize at least some of the NIC functionality. In some embodiments, the NIC can work with a standalone processor or control host in order to offload much of the processing to the control host. The NIC can further handle headers and payload separately where possible, in order to improve the efficiency of processing the various packets.