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.
Which type of address object allows a FortiGate to perform DNS resolution to match traffic based on a domain name?
Wildcard FQDN
Why wrong: Wildcard FQDN also uses domain patterns but still resolves via DNS; however, FQDN is the correct general term. But in FortiOS, 'FQDN' is the exact type for single domain names.
Subnet
Why wrong: Subnet is a fixed IP range, not domain-based.
FQDN
FQDN address objects resolve domain names to IPs via DNS.
Geography
Why wrong: Geography objects match by country IP ranges.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
FQDN
Option C is correct because an FQDN (Fully Qualified Domain Name) address object in FortiGate allows the firewall to perform DNS resolution to match traffic based on a domain name. When a policy uses an FQDN object, FortiGate resolves the domain name to IP addresses via DNS and updates the policy dynamically as the DNS record changes, enabling traffic matching by domain rather than static IP.
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.
Wildcard FQDN
Why it's wrong here
Wildcard FQDN also uses domain patterns but still resolves via DNS; however, FQDN is the correct general term. But in FortiOS, 'FQDN' is the exact type for single domain names.
Subnet
Why it's wrong here
Subnet is a fixed IP range, not domain-based.
FQDN
Geography
Why it's wrong here
Geography objects match by country IP ranges.
Common exam traps
The trap here is that candidates often confuse FQDN with Wildcard FQDN, thinking the wildcard variant is the only one that performs DNS resolution, but both use DNS; the question specifically asks for the type that 'allows' DNS resolution, and the standard FQDN is the foundational object for this purpose.
Detailed technical explanation
Under the hood, FortiGate uses a DNS resolver to periodically query the FQDN and caches the resolved IP addresses with a TTL (Time To Live) from the DNS response. The firewall then creates dynamic entries in the policy lookup table, allowing traffic to be matched even if the destination IP changes, as long as the domain name remains the same. A real-world scenario is when a web application uses a CDN with frequently changing IPs; using an FQDN object ensures the policy remains effective without manual IP updates.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
What to study next
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FAQ
Firewall Policies and NAT — This question tests Firewall Policies and NAT — Read the scenario before looking for a memorised answer..
The correct answer is: FQDN — Option C is correct because an FQDN (Fully Qualified Domain Name) address object in FortiGate allows the firewall to perform DNS resolution to match traffic based on a domain name. When a policy uses an FQDN object, FortiGate resolves the domain name to IP addresses via DNS and updates the policy dynamically as the DNS record changes, enabling traffic matching by domain rather than static IP.
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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Last reviewed: Jun 24, 2026
This NSE4 practice question is part of Courseiva's free Fortinet certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the NSE4 exam.
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