Exercise 1: Telling Three Simultaneous SSH Sessions Apart — Possible Solution
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Explanation:

Per the chapter, "a single TCP connection is uniquely identified by
four values together: source IP, source port, destination IP, and
destination port. This four-value combination -- not any single one
of them -- is what distinguishes one connection from every other
connection happening at the same moment, even between the exact same
two machines." In this scenario, three of those four values are
genuinely identical across all three SSH sessions: the source IP (the
laptop's own address) is the same for all three, the destination IP
(the server's address) is the same for all three, and the destination
port is the same for all three (port 22, per the chapter's own
well-known-ports table for SSH).

The value that differs is the source port. Per the chapter's own
ephemeral-port section, "every connection has two ports, not one: the
well-known port on the server side... and a temporary, dynamically
assigned ephemeral port on the client side." Each time the laptop
opens a new SSH session to the same server, the operating system
assigns that new connection a different, previously-unused ephemeral
port from its own dynamic range (per the chapter, typically
49152-65535). So the three sessions might look like:

Session 1: laptop:51200 -> server:22
Session 2: laptop:51201 -> server:22
Session 3: laptop:51202 -> server:22

Even though the destination IP and destination port are identical
across all three -- exactly as stated in the question -- the source
port differs for each one, which is enough on its own to make each
full 4-tuple unique. The server (and the laptop's own operating
system) uses this complete 4-tuple, not just the destination
information, to track each session as a genuinely separate connection,
directly mirroring the chapter's own two-browser-tab example.

WHY THIS WORKS AS AN ANSWER
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This identifies specifically which of the four values differs (source
port) and which three are identical, using the chapter's own explicit
4-tuple definition rather than vaguely asserting the connections are
"tracked separately" without explaining the actual distinguishing
value.