350-501 Automation and Assurance Practice Question
A network engineer is troubleshooting a NETCONF session that fails to establish between a controller and a router. The router supports NETCONF over SSH on port 830. The controller can reach the router but the session fails. What is the most likely cause?
⚠ Common exam trap
Cisco often tests the distinction between transport-layer failures (SSH host key) and application-layer failures (NETCONF capability or YANG support), leading candidates to incorrectly choose options related to NETCONF configuration rather than SSH authentication.
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
✓
The SSH host key of the router is not in the controller's known_hosts file
The most likely cause is that the SSH host key of the router is not in the controller's known_hosts file. NETCONF over SSH (RFC 6242) requires SSH transport, and the controller must authenticate the router's SSH host key during session establishment. If the host key is missing or mismatched, the SSH handshake fails, preventing the NETCONF session from starting, even though the router is reachable and NETCONF is enabled.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The router's NETCONF capability is disabled
Why it's wrong here
If disabled, the router wouldn't listen on port 830.
- ✓
The SSH host key of the router is not in the controller's known_hosts file
Why this is correct
SSH host key verification failure can cause session failure.
- ✗
The controller is using the wrong port (e.g., 22)
Why it's wrong here
The engineer knows port 830 is correct.
- ✗
The router does not support YANG models
Why it's wrong here
NETCONF sessions can establish even without YANG models, but models are needed for data access.
Go deeper
Related to this question
About these practice questions
One of 971 original 350-501 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-501 practice question is part of Courseiva's free Cisco 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 350-501 exam.