Quick Answer
The answer is that the FortiGate lacks a firewall policy allowing NTP traffic sourced from its own interface IP. This is correct because FortiGate enforces policy-based forwarding for all traffic, including traffic generated by the device itself—such as NTP synchronization requests—meaning that even if the NTP server is reachable, the outbound UDP port 123 packets are dropped without an explicit permit policy. On the Fortinet NSE 4 Network Security Professional exam, this question tests your understanding of local-out traffic and the common trap that self-originated traffic bypasses firewall rules; in reality, it does not. A reliable memory tip is "Self traffic needs a policy too"—always create a policy with the source set to the FortiGate’s interface IP and the destination to the NTP server to resolve a FortiGate NTP synchronization issue.
This NSE4 practice question tests your understanding of system and network administration. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
An administrator wants to synchronize the FortiGate's time with a reliable NTP server. After configuring the NTP server, they notice the time is still incorrect. What could be the issue?
The FortiGate does not have a firewall policy allowing NTP traffic from the FortiGate itself
Traffic from the FortiGate to the NTP server must be allowed by a policy.
The NTP server is not reachable due to a missing route
Why wrong: This is a possibility but less specific than a firewall policy issue.
The FortiGate does not support NTP
Why wrong: It does.
The NTP server is not configured correctly
Why wrong: Not specified.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The FortiGate does not have a firewall policy allowing NTP traffic from the FortiGate itself
By default, FortiGate does not allow traffic sourced from its own IP addresses, including NTP queries, to pass through its interfaces unless an explicit firewall policy permits it. Even if the NTP server is reachable via routing, the FortiGate's own NTP client traffic is subject to the same policy enforcement as any other traffic. Therefore, a firewall policy must be created with the source set to the FortiGate's interface IP and the destination set to the NTP server to allow NTP (UDP port 123) traffic outbound.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
The FortiGate does not have a firewall policy allowing NTP traffic from the FortiGate itself
Why this is correct
Traffic from the FortiGate to the NTP server must be allowed by a policy.
Related concept
Read the scenario before looking for a memorised answer.
The NTP server is not reachable due to a missing route
Why it's wrong here
This is a possibility but less specific than a firewall policy issue.
The FortiGate does not support NTP
Why it's wrong here
It does.
The NTP server is not configured correctly
Why it's wrong here
Not specified.
Common exam traps
The trap here is that candidates assume NTP traffic is automatically allowed for management purposes, but FortiGate treats all traffic, including its own, as subject to firewall policies, so a missing explicit policy is a common oversight.
Detailed technical explanation
FortiGate's implicit deny policy applies to traffic originating from the FortiGate itself, including management traffic like NTP, DNS, and LDAP. This behavior is controlled by the 'set allowaccess' settings on interfaces and the presence of explicit policies. In real-world deployments, administrators often forget to create a policy for the FortiGate's own traffic, leading to time sync failures even when NTP servers are correctly configured and reachable. The NTP client in FortiOS uses UDP port 123 and sends requests from the interface IP, which must be permitted by a policy with source set to 'all' or the specific interface address.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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
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FAQ
System and Network Administration — This question tests System and Network Administration — Read the scenario before looking for a memorised answer..
The correct answer is: The FortiGate does not have a firewall policy allowing NTP traffic from the FortiGate itself — By default, FortiGate does not allow traffic sourced from its own IP addresses, including NTP queries, to pass through its interfaces unless an explicit firewall policy permits it. Even if the NTP server is reachable via routing, the FortiGate's own NTP client traffic is subject to the same policy enforcement as any other traffic. Therefore, a firewall policy must be created with the source set to the FortiGate's interface IP and the destination set to the NTP server to allow NTP (UDP port 123) traffic outbound.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Same concept, more angles
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Variation 1. Which of the following is required to allow a FortiGate to synchronize its clock with an NTP server?
easyWhy A: A FortiGate synchronizes its clock with an NTP server using NTP traffic, which relies on UDP port 123. Without a firewall policy that explicitly permits outbound UDP 123 traffic from the FortiGate to the NTP server, the NTP packets are dropped by the FortiGate's own firewall engine, preventing clock synchronization. This policy is required even for traffic originating from the FortiGate itself, as the FortiGate applies firewall rules to all traffic, including management traffic.
Last reviewed: Jun 24, 2026
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