Abstract: With the rapid development of distributed system technology, three-layer distributed system is the main direction of future development, communication middleware is a indispensable layer. Communication middleware can enlarge the scale of distributed systems, support more users to connect to the server, simplify the communication process of the user and the server, make the communication process of the client and the server more secure, realize the cross-platform application. Currently there are some mature communication middlewares, such as ACE and ICE, but there is a problem that the designers of three-layer distributed system must understand their complex functions and operations, sometime many functions are not used by designers. So designing a small, efficient communication middleware is very important for designers. NESSUS is a popular network vulnerability scanning system in the world which is a distributed system based on C / S and B / S structure. The communication between the client and the server is built on the transport protocol of NTP. This paper focuses on how the NESSUS communicates between the client and the server, packaging the communication module and providing the middleware interfaces, while introducing message send / receive queue buffer pool technology and SSL components. Then a set of small, efficient, secure, cross-platform communication middleware is presented, which is also applicable to other client / server three-layer distributed systems.

Key words: NESSUS, NTP, communication middleware, buffer pool technology, SSL components