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PROFESSIONAL-CLOUD-NETWORK-ENGINEER · Question #158

You are configuring a new HTTP application that will be exposed externally behind both IPv4 and IPv6 virtual IP addresses, using ports 80, 8080, and 443. You will have backends in two regions…

The correct answer is D. Use External HTTP(S) Load Balancing with URL Maps and an X-Forwarded-For header. External HTTP(S) Load Balancing (now called Global external Application Load Balancer) is the only option that satisfies all requirements: it supports both IPv4 and IPv6 VIPs, ports 80/8080/443, multi-region backends with global anycast for lowest latency, URL map-based content…

Submitted by helene.fr· Apr 18, 2026Designing, planning, and prototyping a Google Cloud network

Question

You are configuring a new HTTP application that will be exposed externally behind both IPv4 and IPv6 virtual IP addresses, using ports 80, 8080, and 443. You will have backends in two regions: us-west1 and us-east1. You want to serve the content with the lowest-possible latency while ensuring high availability and autoscaling, and create native content-based rules using the HTTP hostname and request path. The IP addresses of the clients that connect to the load balancer need to be visible to the backends. Which configuration should you use?

Options

  • AUse Network Load Balancing
  • BUse TCP Proxy Load Balancing with PROXY protocol enabled
  • CUse External HTTP(S) Load Balancing with URL Maps and custom headers
  • DUse External HTTP(S) Load Balancing with URL Maps and an X-Forwarded-For header

How the community answered

(24 responses)
  • A
    4% (1)
  • B
    8% (2)
  • C
    4% (1)
  • D
    83% (20)

Explanation

External HTTP(S) Load Balancing (now called Global external Application Load Balancer) is the only option that satisfies all requirements: it supports both IPv4 and IPv6 VIPs, ports 80/8080/443, multi-region backends with global anycast for lowest latency, URL map-based content routing on HTTP hostname and path, and managed autoscaling. To make the original client IP visible to backends, the load balancer automatically adds the X-Forwarded-For header containing the client's IP. Option C mentions 'custom headers', which is a real feature but does not specifically address client IP visibility the way X-Forwarded-For does. Network Load Balancing (A) and TCP Proxy (B) operate at Layer 4 and cannot perform HTTP content-based routing.

Topics

#Load Balancing#External HTTP(S) Load Balancer#URL Maps#X-Forwarded-For

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