In previous sections, we sniffed and injected packets with raw sockets, where we have to do parsing, decoding, creating, and injecting packets all by ourselves. Also, raw sockets are not compatible with all operating systems. There are many third-party libraries that will help us to work with packets. Scapy is a very powerful interactive packet manipulation library and tool that stands out from all these libraries. Scapy provides us different commands, from basic level to advanced level, for investigating a network. We can use Scapy in two different modes: interactively within a terminal window, and programmatically from a Python script by importing it as a library.

Let's start Scapy using the interactive mode. Interactive mode is like Python shell; to activate this, just run Scapy with root privileges in a terminal:

    $ sudo scapy

This will return an interactive terminal in Scapy:

These are some basic commands for interactive usage: