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An IP machine $Q$ has a path to another $IP\ machine\ H$ via three $IP\ routers \ R1, R2,$ and $R3$.

$Q-R1-R2-R3-H$

$H$ 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?

1. Only $I1$ and $I2$
2. Only $I1$
3. Only $I2$ and $I3$
4. Only $I3$ and $I4$