Design And Implementation Of A Linux-based Firewall

In the continuous development of the Internet, information technology has been a tremendous force in the promotion of economic development and social progress, in today's society, a high degree of computerized information resources, both at any time, anywhere, to any person have become increasingly valuable . Whether stored on the server, the workstation or the circulation of information on the Internet, have become the cause of success or failure of a relationship and important key points, thus ensuring the security of information becomes more important. As in recent years developed an important network security technology, firewall technology, at the entrance to the main role is to check the network communication in the network, according to security rules set by the customer in the protection of the premise of internal network security to protect the internal and external network communications.The filewall which brings up by the article aims at protect the safety of Linuxserver,after researching the kernel of Linux.Firstly,the paper brings forward thestate inspection principle in kernel and user space implement method in Linux,improve the tradition packet filtering by the connect tracking technology inNetfilter.Secondly,with the consider of aspects such as firewall policy,totaldesign idea,detail design idea and iptables user space implement,brings forward a all-sided firewall design project.Based on it,it implementated the stateinspection module which was fit on Linux server such as FTP,DNS,SSH,Web,accomplished prompt analysis of data flow state,improve efficiency of firewallfliteration,have realized a safer and reliabler and high-speed effective stateinspection firewall in Linux,and by testing in applying to reality verified itsvalidity and reliability,provide effect for further development of the Linuxfirewall technology.