Which of the following is the most effective technique for identifying live client systems on a LAN?

ICMP Echo Requests send a ping packet to a target IP address and wait for an Echo Reply, confirming the host is alive and reachable on the network. This technique is simple, fast, and universally supported across all IP-enabled devices on a LAN. It forms the standard foundation for host discovery in tools like nmap's ping scan mode (-sn).

TCP FIN scanning is a stealth technique used to probe open ports on already-identified hosts, not a method for discovering which hosts are live on a network.

Traceroute maps the routing path between two endpoints hop by hop and is not designed to enumerate or identify multiple live hosts across a LAN.

DNS Zone Transfer is a DNS replication mechanism that copies zone records between name servers and cannot actively probe or identify live hosts on a network segment.