Deep Packet Inspection (DPI) is a form of network packet filtering that examines the data part (and sometimes the header) of a packet as it passes an inspection point, searching for protocol non-compliance, viruses, spam, intrusions, or other defined criteria to decide whether the packet can pass or if it needs to be routed to a different destination. It is a powerful tool for network management and security, enabling advanced monitoring and control over data traffic, but it also raises significant privacy concerns due to its ability to inspect the content of communications.