JNCIA-SEC Junos OS Security Objects Practice Question
When defining a custom application in Junos OS, you specify the protocol as TCP and set a source port range of 1024-65535 and a destination port of 8080. How does Junos evaluate this application in security policies?
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
✓
It matches TCP traffic destined to port 8080 with a source port falling within 1024-65535.
Custom applications define matching criteria based on IP protocol, source port, and destination port ranges.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
It matches TCP traffic destined to port 8080 with a source port falling within 1024-65535.
Why this is correct
Both source and destination port constraints defined in the application object are enforced during matching.
- ✗
It is automatically converted to a predefined junos-http application by the SRX device.
Why it's wrong here
Junos does not automatically alter custom application definitions to match predefined ones.
- ✗
It requires inspection via an ALG because custom ports are used for HTTP traffic.
Why it's wrong here
Custom applications do not automatically invoke ALGs unless explicitly mapped or associated with standard protocol signatures.
- ✗
It matches any packet destined to port 8080 regardless of source port.
Why it's wrong here
If a source port range is explicitly defined in the application, Junos matches traffic adhering to that constraint.
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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.