This NSE4 practice question tests your understanding of firewall policies and nat. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 administrator notices that traffic from the internal network (10.0.1.0/24) to the internet is not being matched by the intended firewall policy (ID 10). The policy uses source address 'internal_subnet' (10.0.1.0/24) and destination address 'all'. There is another policy (ID 5) with source 'all' and destination 'all' that also matches this traffic. What is the most likely reason policy 10 is not being matched?
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
✓
Policy 5 has a higher priority because it is above policy 10 in the policy list
FortiGate matches firewall policies from top to bottom. Policy 5 is higher in the policy list order than policy 10, so traffic matches policy 5 first and never reaches policy 10.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Policy 5 has a higher priority because it is above policy 10 in the policy list
Why this is correct
Policy order determines matching; first match is used.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Policy 10 is configured with an expired security certificate
Why it's wrong here
Certificates are not related to policy matching.
✗
The source address object 'internal_subnet' is incorrectly configured
Why it's wrong here
The source address is correct; the issue is policy ordering.
✗
Policy 10 has a schedule that is not active
Why it's wrong here
There is no mention of schedule in the scenario.
Common exam traps
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Trap categories for this question
Scenario analysis trap
There is no mention of schedule in the scenario.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
CIDR notation defines the prefix length.
Block size helps identify subnet boundaries.
Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
The required host count determines the smallest suitable subnet.
TExam Day Tips
→Write the block size before choosing the subnet.
→Check whether the question asks for hosts, subnets or a specific address range.
→Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related NSE4 subnetting questions on CIDR, address ranges, and subnet selection.
Firewall Policies and NAT — This question tests Firewall Policies and NAT — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Policy 5 has a higher priority because it is above policy 10 in the policy list — FortiGate matches firewall policies from top to bottom. Policy 5 is higher in the policy list order than policy 10, so traffic matches policy 5 first and never reaches policy 10.
What should I do if I get this NSE4 question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related NSE4 subnetting questions on CIDR, address ranges, and subnet selection.
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?
CIDR notation defines the prefix length.
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Question Discussion
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