Exercise 1: DROP vs. REJECT — Possible Solution
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DROP
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Per this chapter, DROP means "the packet is discarded with no response
of any kind - indistinguishable, from the client's side, from a
timeout caused by anything else." Nothing is sent back to the client
at all.

REJECT
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Per this chapter, REJECT means "an active reply is sent back -
typically a TCP reset or an ICMP 'administratively prohibited' message
- which looks the same as Chapter 6's 'connection refused.'" The
firewall actively responds to say no, rather than staying silent.

WHY DROP IS A DELIBERATE CHOICE, NOT A MISCONFIGURATION
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Per this chapter, "DROP is often preferred specifically because it
gives an attacker less information (a silent void looks the same
whether a port is closed or actively blocked)." Staying silent denies
an attacker the ability to distinguish "blocked" from "nothing there
at all," which is a genuine security benefit, not an oversight. The
chapter also notes REJECT has its own legitimate purpose - "a faster,
cleaner failure for legitimate traffic that isn't allowed" - meaning
neither behavior is inherently wrong; they're two deliberate tradeoffs.

WHY THIS WORKS AS AN ANSWER
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It correctly distinguishes the two behaviors by what the client
actually observes, and explains DROP's specific security rationale
(denying an attacker useful information) rather than treating silence
as simply "no response configured" without a reason.