计算机网络安全和防火墙技术
Title：Problems and Countemeasures of network secunty
Major：Network system management
Name： Hanyan Signature：Supervisor：Liupeng Signature：
Abstract
In recent years, increasing cyber crime, the birth of a large number of hacking sites,network security issues more and more attention. Network security for the country offices, banks, business is crucial, even for schools,even individuals as well. Therefore, the security and confidentiality of network construction is increasingly becoming a key technology, firewall technology is one important part. Firewall is equivalent to a flow control device can be used to monitor or deny the application layer traffic. It is through the establishment of a set of rules and policies to monitor and restrict the flow of data through the firewall to allow legitimate packets, organizing illegal packets,so as to achieve effective protection of internal network security.