This NSE4 practice question tests your understanding of firewall policies and nat. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A network admin has configured a firewall policy allowing traffic from the 'internal' zone to the 'external' zone. The policy uses a service object 'HTTP' (TCP/80). Users report they can access HTTP websites but not HTTPS. The admin confirms no other policies block HTTPS. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
HTTPS traffic is being dropped by implicit deny because no policy matches it
The policy only permits HTTP (TCP/80). HTTPS uses TCP/443, which is not allowed unless a separate service is defined.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The FortiGate needs to perform SSL inspection on HTTPS traffic
Why it's wrong here
SSL inspection is not required for basic HTTPS connectivity; the policy must allow the port.
✗
There is a policy ordering issue; a later policy might block HTTPS
Why it's wrong here
The question states no other policies block HTTPS, so ordering is not the issue.
✓
HTTPS traffic is being dropped by implicit deny because no policy matches it
Why this is correct
Since the policy only allows HTTP, HTTPS falls through to the implicit deny rule and is dropped.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Standard ACLs match source addresses.
✗
The service object 'HTTP' also includes TCP/443 by default
Why it's wrong here
HTTP service object typically only includes TCP/80.
Common exam traps
Common exam trap: ACLs stop at the first match
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Detailed technical explanation
How to think about this question
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
KKey Concepts to Remember
Standard ACLs match source addresses.
Extended ACLs can match source, destination, protocol and ports.
The first matching ACL entry is used.
There is usually an implicit deny at the end.
TExam Day Tips
→Check inbound versus outbound direction.
→Read the ACL from top to bottom.
→Look for a broader permit or deny above the intended line.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Real-world example
How this comes up in practice
A security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.
What to study next
Got this wrong? Here's your next step.
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related NSE4 ACL questions on filtering logic and placement.
Firewall Policies and NAT — This question tests Firewall Policies and NAT — Standard ACLs match source addresses..
What is the correct answer to this question?
The correct answer is: HTTPS traffic is being dropped by implicit deny because no policy matches it — The policy only permits HTTP (TCP/80). HTTPS uses TCP/443, which is not allowed unless a separate service is defined.
What should I do if I get this NSE4 question wrong?
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related NSE4 ACL questions on filtering logic and placement.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Standard ACLs match source addresses.
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Question Discussion
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