The port scanning technique that involves resetting the TCP connection between the client and server abruptly before the completion of the three-way handshake, thereby leaving the connection half-open, is known as a Stealth scan (also referred to as a SYN scan). This technique allows the scanner to inquire about the status of a port without establishing a full TCP connection, making the scan less detectible to intrusion detection systems and less likely to be logged by the target. It's a method used to discreetly discover open ports on a target machine without establishing a full connection that would be visible in logs.References:CREST materials often cover different types of network scanning techniques, including Stealth scans, explaining their methodologies, purposes, and how they can be detected or mitigated.