The syntax to trigger a TCP Scan is:

nmap -sT <IP address>

A TCP Scan (sometimes referred to as a connect scan) is one of the few types of scans available to a non-privileged user. This is due to the fact that there is no manipulation of the raw packets. Nmap will ask the underlying operating system to establish a connection with the target port on the target machine.

To identify an open port using a TCP Scan, the full TCP 3 way handshake is conducted (SYN, SYN-ACK, ACK). If a port is closed the communication will be SYN, RST.

‍