Final answer:
To perform passive footprinting against Company XYZ Inc.'s web server, you would use the Nmap tool. Ettercap and Ethereal/Wireshark are not specifically designed for passive footprinting, while Netcratt is not a known tool for this purpose.
Step-by-step explanation:
If you want to perform passive footprinting against Company XYZ Inc.'s web server, you would use the Nmap tool. Nmap is a powerful network scanning tool that can be used to discover hosts and services on a network, as well as gather information about those hosts and services. The tool allows you to perform host discovery, port scanning, version detection, and more.
Ettercap is a network sniffing and interception tool, used primarily for man-in-the-middle attacks and network analysis. Ethereal is an older name for what is now known as Wireshark, which is a network protocol analyzer. While both Ettercap and Ethereal/Wireshark can be used for network analysis, they are not specifically designed for passive footprinting.
Netcratt is not a known tool for passive footprinting. It is possible that this is a misspelling or a misspelling of a relatively unknown or custom tool.