What is the role of packet filtering in protecting network boundaries?

Packet filtering works to protect network boundaries from unauthorized access by examining incoming and outgoing packets based on a set of predefined rules. These rules determine whether a packet should be allowed to pass through the network boundary or should be blocked. Packet filtering typically operates at the network layer of the OSI model and can filter packets based on criteria such as source and destination IP addresses, port numbers, protocol types, and other header information.

When a packet reaches a network device configured with packet filtering, the device compares the packet’s information to the filtering rules and either permits or denies its passage. By blocking packets that do not meet the defined criteria, packet filtering helps prevent unauthorized access to the network and protects against various types of network attacks, such as denial-of-service attacks, port scanning, and other malicious activities.

Overall, packet filtering acts as a first line of defense for network security by controlling the flow of traffic at the network boundary and enforcing security policies to minimize the risk of unauthorized access and potential threats.