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Interview question · Network Security & Protocols

Stateless versus stateful firewalls, NAT, and egress filtering: what does each actually protect?

NAT is not a firewall, and inbound rules are only half a policy. Interviewers check whether you know what each device decides, and why the outbound direction is where breaches are contained.

easyNewPreparation tags: Cisco, Palo Alto Networks, Check PointUpdated Nov 2026

NAT is not a firewall, and inbound rules are only half a policy. Interviewers check whether you know what each device decides, and why the outbound direction is where breaches are contained.

Make your first attempt

What would you say before reading the answer?

  1. 01 State the assumptions your answer depends on.
  2. 02 Explain the mechanism and choose a control.
  3. 03 Name a condition that would change your decision.

The worked answer includes an approach, scoring criteria and follow-up questions. Compare the reasoning with your own.

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What if · the follow-ups in this answer

The answer works through 6 follow-ups like an interviewer would

A junior engineer asks how firewalls, NAT and egress control relate to each other, after assuming NAT was protecting the office.

  1. How do stateless and stateful filters differ?
  2. What do next-generation firewalls add?
  3. Is NAT a security control?
  4. Why does egress control matter?
  5. How would you put them together?
  6. How would you explain the relationship?

Each rung has a nudge, a model answer, the principle that carries over and the weak answer to avoid. Sign in free to open it.

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