https://en.wikipedia.org/wiki/Turnstile#:~:text=A%20turnstile%20(also%20called%20a,%2C%20a%20pass%2C%20or%20similar.

Explanation
Nmap is a tool that is used to scan IP addresses and ports in a network and to detect installed applications.
Nmap can help a security administrator determine the services running on a server by sending various packets to the target and analyzing the responses. Nmap can also perform various tasks such as OS detection, version detection, script scanning, firewall evasion, and vulnerability scanning.
References: https://www.comptia.org/certifications/security#examdetails
https://www.comptia.org/content/guides/comptia-security-sy0-601-exam-objectives https://nmap.org/

Push notifications are a type of technology that allows an application or a service to send messages or alerts to a user's device without requiring the user to open the application or the service. They can be used for multi-factor authentication (MFA) by sending a prompt or a code to the user's device that the user has to approve or enter to verify their identity. They can be non-disruptive and user friendly because they do not require the user to remember or type anything, and they can be delivered instantly and securely.