What is the term for the basic technique that checks a range of IPs to identify live hosts?

• A. Angry IP Scanner
• B. A ping sweep
• C. ICMP ECHO ping scans
• D. UDP Ping Scan

Answer: (C)

Identifying live hosts in a subnet is done by sending a probe to each address and seeing which devices respond. The most precise way to describe this exact technique is ICMP ECHO ping scans, because it specifies that ICMP Echo requests (the classic ping) are used to check reachability. A host that replies is considered alive, giving you a list of active devices.

While ping sweep describes the general idea of scanning a range for responding hosts, the ICMP ECHO ping scans phrasing emphasizes the specific method—the ICMP Echo request. Tools like Angry IP Scanner perform such scans, but the core concept here is the ICMP Echo probe. Using UDP probes (UDP Ping Scan) isn’t the standard for basic host discovery and often yields unreliable results due to many hosts not replying to UDP.