Google PCA Manage implementation of cloud architecture Practice Question
A company is migrating a legacy application to Google Cloud. The application has a stateful TCP-based protocol that requires client IP persistence. They plan to use a load balancer. Which load balancer type should they choose?
⚠ Common exam trap
Test-takers frequently confuse 'TCP proxy' with 'TCP passthrough,' assuming any TCP-capable load balancer preserves client IP, but only the passthrough (Network Load Balancer) avoids terminating the TCP connection and maintains the original source IP.
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
✓
External Network Load Balancer (passthrough)
The External Network Load Balancer (passthrough) is the correct choice because it preserves the original client IP address via direct server return (DSR) and does not terminate the TCP connection. This is essential for stateful TCP-based protocols that require client IP persistence, as the backend instances see the actual client IP and can maintain session state.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
External HTTP(S) Load Balancer
Why it's wrong here
This is for HTTP/HTTPS, not stateful TCP; also terminates connections and does not preserve client IP.
- ✗
Internal TCP/UDP Load Balancer
Why it's wrong here
Internal LB is for traffic within the VPC, not external client traffic.
- ✗
External TCP Proxy Load Balancer
Why it's wrong here
TCP Proxy terminates the connection, so the backend sees the proxy's IP, not the client IP.
- ✓
External Network Load Balancer (passthrough)
Why this is correct
This is a passthrough load balancer that preserves the client IP for TCP/UDP traffic.
Visual reference
Go deeper
Related to this question
Learn chapter
Introduction to Google Cloud Platform
Key term
IP address
An IP address is a unique numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.
Key term
TCP
TCP (Transmission Control Protocol) is a core internet protocol that ensures data is sent reliably and in order between devices over a network.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCA practice question is part of Courseiva's free Google Cloud 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 PCA exam.