Port security is a feature that restricts input to a switch port by limiting and identifying MAC addresses of the devices allowed to access the port. This prevents unintended connections from unauthorized devices or spoofed MAC addresses. Port security can also be configured to take actions such as shutting down the port or sending an alert when a violation occurs. Reference: https://partners.comptia.org/docs/default-source/resources/comptia-network-n10-008-exam-objectives-(2-0), https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/16-10/configuration_guide/sec/b_1610_sec_9500_cg/b_1610_sec_9500_cg_chapter_0101010.html

The dig command is used to query the NSs for a remote application. It is a command-line tool that is commonly used to troubleshoot DNS issues. When used with specific options, dig can be used to obtain information about domain names, IP addresses, and DNS records. Reference: Network+ Certification Study Guide, Chapter 3: Network Infrastructure

FTP (File Transfer Protocol) is a client-server based protocol, meaning that the two computers involved communicate with each other in a request-response pattern. The client sends a request to the server and the server responds with the requested data. This type of architecture is known as client-server, and it is used for many different types of applications, including FTP. Other architectures, such as service-oriented, connection-oriented, and data-centric, are not used for FTP.