DPI means Deep Packet Inspection
At DPI, content is looked at the data transmitted over the network. If you send an old-fashioned handwritten letter, the postal company only looks at the envelope to see where it should go, if DPI is used, the letter itself will be read. A virus scanner and a Firewall also make Gebrbuik of DPI to check what happened on the computer or on the network. DPI was mainly in the news because KPN used it to analyze the data of customers, so that one could block (and re-enable) certain services if it was paid.
Deep Packet Inspection is watching YOU [YouTube] SAHs_1ZuXgI [/youtube]