JNCIA-SEC Network Address Translation Practice Question
An administrator creates a Destination NAT rule that translates incoming traffic on public IP 203.0.113.100 to private IP 10.10.10.100. However, when inspecting sessions using 'show security flow session', the translation shows the correct destination IP, but the application traffic fails. Further inspection reveals that the internal server listens on port 8080, whereas the external traffic arrives on port 80. How should the Destination NAT rule be configured to handle this port translation?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Define a destination NAT pool that specifies port 8080, and reference this pool in the Destination NAT rule matching port 80 traffic.
Destination NAT in Junos allows port translation by specifying the destination port in the pool configuration (e.g., setting the pool port to 8080 while matching external traffic on port 80).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Define a destination NAT pool that specifies port 8080, and reference this pool in the Destination NAT rule matching port 80 traffic.
Why this is correct
Specifying the translated port within the destination NAT pool configuration enables port translation (DNAT + port forwarding).
- ✗
Enable a security ALG for HTTP traffic to automatically remap port 80 to port 8080.
Why it's wrong here
HTTP ALGs do not dynamically remap ports across NAT boundaries; port mapping is done via NAT configuration.
- ✗
Configure a Static NAT rule with port override statements under the security policy.
Why it's wrong here
Port overriding is handled in NAT pool/rule configurations, not security policies.
- ✗
Change the Junos system service port mapping table globally.
Why it's wrong here
Junos does not use a global system service port mapping table for destination NAT port forwarding.
Visual reference
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official Juniper Networks exam blueprint
This JNCIA-SEC practice question is part of Courseiva's free Juniper Networks 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 JNCIA-SEC exam.