In the netstat command, which parameter is used to display all active TCP connections on which the computer is listening?

The correct parameter to display all active TCP connections on which the computer is listening when using the netstat command is -a. This parameter stands for "all" and shows both listening and non-listening (established) TCP connections, along with other information about the network connections currently active on the system, including UDP connections.

Using the -a option is important for a comprehensive view of all network activity, including services that are waiting for incoming connections (listening) and those that are already established. This makes it an essential tool for analyzing network performance, troubleshooting connectivity issues, and monitoring security by keeping track of which ports are open and what services are actively communicating.

The other parameters have different functions: -e displays Ethernet statistics, -n shows the numerical form of addresses and port numbers instead of resolving them to their respective hostnames or service names, while -s provides statistics by protocol. Each parameter serves its specific role, but -a is the one you need to see all active TCP connections, including those in the listening state.