Based on this scenario, what is the MOST cost-effective solution to this problem?
Remove the application from the ALB. Delete the ALB and change Amazon Route 53 to direct traffic to the instance running the application.
Remove the application from the ALCreate a Classic Load Balancer in its place. Direct traffic to the application using the HTTP protocol.
Alter the application code to inspect the X-Forwarded-For header. Ensure that the code can work properly if a list of IP addresses is passed in the header.
Alter the application code to inspect a custom header. Alter the client code to pass the IP address in the custom header.
Explanations:
Removing the application from the ALB and directing traffic through Amazon Route 53 would eliminate the load balancing feature, compromising scalability and high availability. It also does not solve the problem of client IP visibility, as client IPs would still be masked.
Switching to a Classic Load Balancer does not solve the IP address visibility issue either, as Classic Load Balancers also do not forward the original client IP. This option also compromises the ability to utilize advanced features provided by the ALB, such as path-based routing and host-based routing.
Altering the application code to inspect theX-Forwarded-Forheader is the most effective solution. The ALB automatically adds this header to requests, preserving the original client IP address. This approach allows the application to maintain its ability to scale horizontally while retaining client IP visibility, all at minimal additional cost.
Using a custom header to pass the IP address would require changes in both the client and server code, increasing complexity and potential for errors. Moreover, this approach does not leverage the existing capabilities of the ALB, such as theX-Forwarded-Forheader, making it less efficient and more cumbersome compared to option C.
I value that the answer is:
Alter the application code to inspect the X-Forwarded-For header. Ensure that the code can work properly if a list of IP addresses is passed in the header.