Design And Implementation Of Icap-client Based On Improved Lru Algorithm

As the widely use of internet, network attacking is also becoming complicated and frequent.Traditional antivirus solutions such as of gateway and desk prevention could not meet the requirement of users. Only if kinds of network basic equipment and advanced virus scanning technique could be combined tightly and orderly, defend ability for complicated mingle threaten could be strengthened.This paper proposes a kind of measure which can scan web-virus with advanced virus-scanning engine in collaboration with gateway and firewall.ICAP Client module using ICAP protocol is realized and integrated with gateway and leading third-party virus protection software-hardware; this could prevent virus from spreading in LAN. This module could scan outer virus using ICAP Server and memory virus scanning result. In the replacing processing of restoring many link scanning results, improved LRU is used not repetitive scanning the resources which are scanned and considered safe by ICAP Server to quicken the speed of surfing web pages.Started from the demanding of network safety and the situation of web-pages-virus prevention, this paper proposes the research direction and the structure.The backgrounds of HTTP and ICAP are simply introduced, the content and meaning of structure and key field are analyzed detailed, the encapsulation of ICAP request message and decapsulation of ICAP response message are designed and implemented according to the results of analysis, ICAP Client module is designed and implemented. Collaboration work system module of ICAP Client, ICAP Server and gateway is presented. It is implemented that ICAP Client and ICAP Server can make communicate with each other. Storing of outer virus scanning results by ICAP Server is implemented and replacing strategy using improved LRU in list is used. ICAP Client's function and performance is tested in simulated network environment. The invasion of web-pages-virus is greatly decreased if LAN is equipped with ICAP client module. The improved LRU could enhance the performance and efficiency of ICAP Client module.