What is a network packet?

A network packet is a small unit of data sent across a network; larger messages, files and web pages are split into many packets and reassembled at the other end. Each packet has a header, like the envelope of a letter, with the sender and recipient addresses and ports, and a body with the content itself. Encryption protects the body, but much of the header stays readable so the network can deliver it. Security tools that capture packets can read those headers and a few unencrypted protocol fields; NetSenX does this where packet capture is enabled and never decrypts the content.

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