When is TCP Connect scanning typically used?

TCP Connect scanning is often employed in situations where the user conducting the scan does not have the necessary permissions to perform more covert forms of scanning, such as half-open scanning (also known as SYN scanning). In TCP Connect scanning, the scanner completes the full three-way handshake, establishing a connection with the target system. This method is straightforward; it relies on the fact that a complete connection will indicate whether a port is open or closed.

Since TCP Connect scanning requires the user to be able to establish a full connection, it is particularly useful when a user is restricted in terms of permissions and cannot utilize techniques that do not complete the handshake. This is often the case on networks where security controls are in place that will block or restrict more stealthy scanning attempts. Thus, TCP Connect scanning can be a preferred method for users who need more visible results and are restricted in their ability to utilize more covert methodologies.