preface
The so-called "firewall" refers to a method of separating the intranet and the public access network (such as the Internet), which is actually an applied security technology and isolation technology based on modern communication network technology and information security technology. It is increasingly used in the interconnected environment of private and public networks, especially in the Internet network.
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First, the basic concept of firewall
Firewall definition: is a network device with security features:
❖ Isolated network:
▪ Isolate networks that need to be protected from untrusted networks, hide information, and secure them
Second, the basic function of the firewall
Basic functions of the firewall: ❖Access control❖Attack protection❖Redundant design❖Routing, switching❖Logging❖Virtual Private Network VPN❖NAT
Third, firewall products and manufacturers
Fourth, regional isolation
Firewall Zone Concept: ▪ Internal Zone ▪DMZ Zone: Called "Quarantine Zone", also known as "Demilitarized Zone/Ceasefire Zone" ▪ Outer Zone
Fifth, the classification of firewalls
•By firewall form 1.Software firewall 2.Hardware firewall•Implement 1.Packet filtering firewall by technology 2.State detection packet filtering firewall 3.Application (proxy) firewall 4.WAF firewall 5.Application layer firewall
Sixth, the development history of the firewall
▪ Packet filtering firewall one of the earliest firewall technologies, simple function, configuration of complex ▪ application gateway / application proxy firewall the earliest firewall technology two, low connection efficiency, slow ▪ speed state detection firewall modern mainstream firewall, fast speed, easy configuration, more ▪functions DPI firewall (Deep Packet Inspection) The future firewall development direction, can detect the seventh layer of data at high speed