Definition
Host discovery is the process of identifying active devices on a network. It involves sending probes or queries to potential IP addresses and analyzing the responses to determine which hosts are online and reachable. This fundamental network reconnaissance technique is crucial for network administrators, security analysts, and penetration testers to understand the scope of a network and identify potential targets or assets. For instance, a network administrator might use host discovery to create an inventory of all devices connected to their corporate network. It differs from port scanning, which focuses on identifying open services on already discovered hosts. Understanding host discovery is essential for domains like network security, network administration, and penetration testing, appearing in certifications such as CompTIA Security+ and Network+.