|Que.||An IP machine Q has a path to another IP machine H via three IP routers R1, R2, and R3.
H acts as an HTTP server, and Q connects to H via HTTP and downloads a file. Session layer encryption is used, with DES as the shared key encryption protocol. Consider the following four pieces of information:
[I1] The URL of the file downloaded by Q
[I2] The TCP port numbers at Q and H
[I3] The IP addresses of Q and H
[I4] The link layer addresses of Q and H
Which of I1, I2, I3, and I4 can an intruder learn through sniffing at R2 alone?
|a.||Only I1 and I2|
|c.||Only I2 and I3|
|d.||Only I3 and I4|
|Answer:Only I2 and I3|