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5.1 Introduction to Access Control List
The full name of ACL is Access Control List ( Access Control List), which is used to limit network traffic and improve network performance; provide control means for communication flow; provide basic security means for network access.
5.1.1 Fundamentals
ACL uses packet filtering technology to read the information in the third layer and fourth layer packet headers (such as source address, destination address, protocol port, port number, etc.) on the router, and filter the packets according to the pre-defined rules.