Nmap port scanner/TCP scan
This service will start by initiating (SYN) connection on each port on a target host. If the port is open, the host will respond with (SYN, ACK). The connection is closed with a reset (RST) sent by the initiator:
This service will start by initiating (SYN) connection on each port on a target host. If the port is open, the host will respond with (SYN, ACK). The connection is closed with a reset (RST) sent by the initiator: