This guide covers configurations for HAProxy. Specifically, in
The instance will work in pure TCP mode. A full-duplex connection will be established between clients and servers, and no layer 7 examination will be performed. This is the default mode. It should be used for TLS.
global to a reasonable level. HAProxy will queue
requests beyond that value.
"set-header" does the same as "add-header" except that the header name is first removed if it existed. This is useful when passing security information to the server, where the header must not be manipulated by external users. Note that the new value is computed before the removal so it is possible to concatenate a value to an existing header.
HAProxy Configuration Guide - http://cbonte.github.io/haproxy-dconv/1.8/configuration.html