Question

A company runs a payment processing API behind a Network Load Balancer (NLB) with targets registered by instance ID across three Availability Zones. The security team requires that the backend EC2 instances see the original client source IP addresses in their application logs. Additionally, the operations team reports that traffic is being distributed unevenly — some AZs receive far more connections than others, causing hot spots. The NLB currently has cross-zone load balancing disabled. Which combination of actions will preserve original client IPs AND resolve the uneven traffic distribution?

Accepted Answer

Keep the targets registered by instance ID (which preserves client IP by default for NLB) and enable cross-zone load balancing on the NLB.

Answer

Re-register the targets by IP address and enable client IP preservation via a target group attribute, then leave cross-zone load balancing disabled.

Answer

Enable proxy protocol v2 on the target group and configure Route 53 weighted records pointing at each AZ's NLB node to balance traffic.

Answer

Place an Application Load Balancer in front of the NLB, enable the X-Forwarded-For header, and turn on cross-zone load balancing on the ALB.