Professional Mail Service System Design And Implementation

The Design & Implementation of FSMail is a child-subject of "Network Multi-function Server", a project funded by Electronic Development Funds of Ministry of Information Industry. With the explosively growing of the Internet at present, email is becoming a main carrier of the information exchange and the most common funtion. Meanwhile, in the domestic market there is a lack of the professional email system with high performance, reliance and security, which is suitable to middle or small enterprises and of our own knowledge rights. Thus, FSMail is coming into being.In this thesis, firstly, it discusses and summarizes the basic theories, working principles and corresponding protocols. Through analysing and comparing different internal architectures of network server, it brings up process-pool-based SMTP Server, POP3 Server and WMG Server, and the MTA Server based on the Single Process Concurrent Service(SPCS) architecure. At the same time, the resolvement of critical network I/O issues related to SPCS is analyzed and figured out. FSMail adopts and implements the asynchronous event driven mechanism, with all those network I/O operations in the server working under the non-blocking style; accomplishes object-oriented heap with the dynamic array, adapted to any type of data; adopts the multi-queue scheduling mechanism based on a FSM, easily to fulfill the extentions of delivery funtions; fulfills the non-blocking domain name resolvement mechanism and the caching of the resolved results; implements the non-blocking user database management and the caching of the user data recently accessed; uses the unified memory pool management,avoiding the memory leakage and improving the performance of the FSMail server; lastly, implements the log management server based on the C/S mode, eliminating the inconsistency of the logging metadata and being adapted to any kind of application logging.The testing about the functions and the performance of FSMail approves that FSMail reaches our designing goals and has accomplished high performance.