200-201 Question 304
Single answerA cybersecurity analyst is investigating a suspected malicious connection between a client and a server. The server is running a web service on port 443, and the client is using a randomly assigned port. Which of the following best describes how the client and server ports are used in this scenario?
- A
The server uses a well-known port, and the client uses an ephemeral port to establish the connection.
- B
The client and server both use well-known ports to communicate.
- C
The client uses a well-known port, and the server uses an ephemeral port to establish the connection.
- D
The client and server both use ephemeral ports to communicate.
Show answer and explanation
Correct answer: A
Explanation
In a typical client-server communication, the server uses a well-known port to provide its service (e.g., port 443 for HTTPS), while the client uses an ephemeral port (a temporary, randomly assigned port) to initiate the connection. This distinction allows the server to be reliably reachable on a specific port while enabling the client to establish multiple connections without port conflicts.
- A. Correct.
Correct: The server uses port 443, which is a well-known port for HTTPS, and the client uses an ephemeral port (a randomly assigned port above 1023) to establish the connection.
- B. Incorrect.
Incorrect: The server uses a well-known port (443), but the client does not use a well-known port; it uses an ephemeral port.
- C. Incorrect.
Incorrect: The client does not use a well-known port; it uses an ephemeral port, while the server uses a well-known port (443).
- D. Incorrect.
Incorrect: The server uses a well-known port (443), not an ephemeral port, for the web service.