Based on the Three-Layer Virtual Host System, we design and implement one WWW Virtual Host System and carefully discuss the design of FTP and EMAIL Virtual Host Systems.

• 根据三层结构的虚拟主机技术，本文阐述了WWW虚拟主机系统的工作原理，总体设计和实现方案，并讨论了FTP和EMAIL虚拟主机系统的设计。