Research of network security and firewalls techniques

As the key facility that maintains the network security, firewalls take the purpose of establishing an obstacle between trust and trustless network, and put corresponding safety strategy into practice. In this paper, the computer network security and the techniques of firewalls were mainly discussed, the concept and classification of the firewalls were introduced. It also introduced three kinds of basic implement techniques of the firewalls: Packet filtering, Application Proxy and Monitor model in detail. Finally, described the trend of development of the firewalls techniques in Internet briefly.