What must the developer do to capture the client public IP addresses in the log file?

Explanations:

Adding a Host header to the log configuration does not affect the capture of the client’s IP address. The Host header contains the domain name of the server being requested, not the client’s IP.

Installing the Amazon CloudWatch Logs agent would allow logging to CloudWatch, but it does not change what the HTTP server logs. The logs would still only capture the ALB IP unless modified to include the client IP.

The AWS X-Ray daemon is used for tracing requests in applications, not for capturing client IP addresses in log files. It does not modify the log output to include the X-Forwarded-For header.

Adding an X-Forwarded-For header to the HTTP server log configuration allows the server to log the original client IP address forwarded by the ALB. This is the standard way to capture the true client IP in scenarios where requests pass through a load balancer.