Preserve Source IP Address of Original Layer 3 Payload

B.

If you want to preserve the source IP address of the original layer 3 payload while deploying a global external TCP load balancing solution, you should use a Network Load Balancer.

Explanation:

HTTP(S) load balancers are designed to distribute HTTP and HTTPS traffic to backend services. They operate at the application layer (layer 7) of the OSI model and modify the source IP address of the incoming packets with their own IP address. Therefore, HTTP(S) load balancers do not preserve the original source IP address of the client.

Internal load balancers are used to balance traffic within a virtual network, such as in Azure or Google Cloud. They are not suitable for external traffic.

TCP/SSL proxy load balancers operate at the transport layer (layer 4) of the OSI model and provide SSL offloading capabilities. They can preserve the original source IP address of the client, but they are not designed for global external load balancing.

Network Load Balancers, on the other hand, are designed to distribute traffic at the network layer (layer 3) of the OSI model. They operate using IP protocol and forward traffic to backend instances without modifying the source IP address. Therefore, they can preserve the original source IP address of the client. Network Load Balancers are suitable for global external load balancing scenarios.

In summary, if you want to preserve the source IP address of the original layer 3 payload while deploying a global external TCP load balancing solution, you should use a Network Load Balancer.