Scapy is a tool that allows the user to craft and inject custom packets into the network. This tool can be leveraged to build ICMP protocol requests and inject them into the network to analyze the response. This specific recipe will demonstrate how to use Scapy to perform layer 3 discovery on remote hosts.
Using Scapy to perform layer 3 discovery does not require a lab environment, as many systems on the Internet will reply to ICMP echo requests. However, it is highly recommended that you perform any type of network scanning exclusively in your own lab unless you are thoroughly familiar with the legal regulations imposed by any governing authorities to whom you are subject. If you wish to perform this technique within your lab, you will need to have at least one system that will respond to ICMP requests. In the examples provided, a combination of Linux and Windows systems are used. For more information on setting up systems in a local...