[lcalcote]

"That's because ELBs forward requests to backend instances without modifying the request headers and the client IP is not sent in case of TCP load balancing." - - not sure this is quite what the author meant?

[ApsOps]

In case of TCP load balancer, the headers are sent unmodified and backend instances receive the ELB's IP as the client IP. This is described in the AWS docs - http://docs.aws.amazon.com/elasticloadbalancing/latest/class...