防火墙 讲解（Firewall explanation）.docVIP

防火墙 讲解（Firewall explanation） This article is contributed by struggle1985 Ppt documents may experience poor browsing on the WAP side. It is recommended that you first select TXT, or download the source file to the local view. Firewall Foundation One Will hackers be interested in our network? For hackers, as long as we see a little bit of light from the system vulnerabilities, it will be ready to protect our network - firewall Two Firewall concept A defense system between the local network and the external network can isolate the connection between the risk area and the secure area, but does not prevent access to the risk area Three Firewall function Filtering unsafe services and illegal user control, access to special sites, providing reliable nodes to monitor Internet security access and early warning, and achieve the companys security policy Four Firewall function To prevent the exposure of internal network structure, can be arranged in the NAT firewall, which can protect the internal network, but also can solve the problem of the shortage of address space is a best place to audit and record Internet use cost to set up a single segment, physically placed WWW, FTP and Mail server. Five Classification of firewalls Packet filter firewalls (represented by Checkpoint and PIX) proxy firewalls (represented by NAIs firewall) Six Packet filtering technology Seven Eight Nine Ten Eleven Twelve The advantages of packet filtering technology You can use this method when you need to communicate constantly in the network. It is completely transparent to users and can be implemented by common routers Thirteen The disadvantages of packet filtering technology Packet filtering is achieved by setting specific data packet filtering rules, in order to achieve the function of filtering, packet filtering criteria must be set very complex. Greatly reduces the packet filtering speed. Because the packet filter is working in the OSI model of the network layer and transport layer for high-level