JNCIA-SEC Network Address Translation Practice Question
An administrator configures a Source NAT pool with multiple IP addresses. By default, how does Junos OS allocate port and IP addresses from this pool for new sessions?
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
✓
Sequential or round-robin allocation across the pool addresses.
By default, Junos OS uses deterministic or round-robin / sequential address allocation from source NAT pools, pairing source IPs with available ports across the pool addresses.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Using only the first IP in the pool until port exhaustion occurs before utilizing subsequent IP addresses.
Why it's wrong here
Junos distributes sessions across pool addresses rather than exhausting a single IP first unless configured otherwise.
- ✗
Hashing the internal source IP and port to bind it to a fixed pool IP (Persistent NAT).
Why it's wrong here
Persistent NAT is an optional feature ('persistent-nat') that must be explicitly enabled; it is not the default behavior.
- ✗
Randomized IP selection for every new session regardless of source IP.
Why it's wrong here
Random allocation is not the default method for source NAT pool address selection.
- ✓
Sequential or round-robin allocation across the pool addresses.
Why this is correct
Junos allocates addresses from source NAT pools sequentially or using round-robin distribution by default.
Visual reference
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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.