Design And Implementation Of Security For DHCP Relay

With the development of the Internet, almost everyone has the demand of using network resources, but the premise is to get an IP address. In the small LAN, it is possible to manually configure the network address or parameters for hosts. However, due to the popularity of laptop computer, network users are pretty dynamic, static configuration is no longer applicable. The emergence of dynamic host configuration protocol has solved this problem. It can be more rational and efficient allocating network resources to meet the growing network users and increasingly complex network.Firstly, this article gives the basic concept of DHCP protocol and its security problems, introduces the basic principles of DHCP and network security technology to eliminate DHCP security threats, which is a theoretical foundation for the implementation of DHCPv4 relay security. Then analyzes the functions of DHCP system, using structured design methodology to design, gives the relationship between DHCP system and external modules and module decomposition for DHCP system. Based on this, proposed a DHCPv4 relay safety scheme, including packet parse solutions, dealing with option 82, strategy of relay safety, focusing on the strategy of DHCPv4 relay client information entry management and security entry management.At last, this paper proposes the system test ideas, methods and testing network environment for DHCPv4 relay, analyzes the problems encountered during testing, and gives the solutions. Test results show that the DHCPv4 relay is able to forwarding request and response packets, deal with option 82, manage client information entry, display configuration and other information and shield illegal clients' request. The system has certain safety and achieves the expected goal, could work well with other companies'equipment, has a broad prospect of application.