1Z0-1072-26 Networking Practice Question
You are configuring an OCI Public Load Balancer and notice that backend instances are marked as unhealthy. Upon inspecting the health check URL on the backend server via curl, it returns HTTP 200. What is the most likely reason the load balancer still reports them as unhealthy?
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
✓
Security lists or NSGs on the backend instances are blocking traffic from the Load Balancer subnet on the listener/health check port.
If backend servers return HTTP 200 locally but are unhealthy in the load balancer, security list rules or NSGs on the backend subnet are likely blocking incoming health check probes from the load balancer subnet.
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 VCN has an Internet Gateway attached.
Why it's wrong here
Internet Gateways do not interfere with internal load balancer health checks.
- ✗
The load balancer shape is set to 10 Gbps instead of 100 Mbps.
Why it's wrong here
Load balancer bandwidth shapes do not cause health check failures if ports are open.
- ✓
Security lists or NSGs on the backend instances are blocking traffic from the Load Balancer subnet on the listener/health check port.
Why this is correct
Backend security rules must allow incoming health check probes from the load balancer.
- ✗
The NAT Gateway is misconfigured.
Why it's wrong here
Load balancer health checks originate internally from the LB subnet, not via a NAT gateway.
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 Oracle exam blueprint
This 1Z0-1072-26 practice question is part of Courseiva's free Oracle 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 1Z0-1072-26 exam.