When computers performs network communication, it’s essentially inter-process communication across operating systems. When communicating between processes within the same operating system, the process exchanges data through pipes, FIFOs, shared memory, etc{1}. The data itself does not change. In network communication, because the operating system is spanned, the process needs to help locate the remote process by using the network layer and transport layer module provided by the operating system. This article briefly describes the data (encapsulation layer) of the interprocess communication when it interacts across the TCP/IP network protocol stack, data encapsulation, transmission and decapsulation.

VirtualBox is a powerful x86 and AMD64/Intel64 virtualization software(VBox for short), which can be used to construct kinds of debug or test network environments, to capture or analyse the packets in the test network. Sometimes, for the sake of security, some virtual hosts run parallely on the same physical platform to isolate each other, decrease complexity. Sometimes, Vbox is used as hack tools to hide from tracking. All these usages are based on the network configuration of Vbox itself. This article is about the network configurations and the topology of each configuration.