John works as an Ethical Hacker for uCertify Inc. He wants to find out the ports that are open in uCertify's server using a port scanner. However, he does not want to establish a full TCP connection.

TCP FIN scanning sends a FIN packet to provoke a RST from closed ports, which is a different stealth technique and does not involve SYN-based half-open behavior.

Xmas tree scanning sets the FIN, PSH, and URG flags simultaneously to elicit responses from closed ports, making it a distinct method unrelated to half-open connections.

TCP SYN/ACK is a reply packet sent by an open port during the handshake, not an active scanning technique initiated by the scanner.

TCP SYN scanning works by sending a SYN packet to a target port and waiting for a response. If the port is open, the target replies with SYN/ACK, but the scanner immediately sends a RST to tear down the connection before it is fully established. This avoids completing the three-way handshake, meaning no full TCP connection is ever logged.