When APIcast is configured with https_proxy, and the environment variable THREESCALE_PORTAL_ENDPOINT is configured to the value of the OpenShift route, the connection to fetch the json configuration will go through the proxy, however DNS resolution is still performed on the gateway, so the proxy will receive a CONNECT request similar to the following:

CONNECT 165.71.36.168:80 HTTP/1.1
Host: server.example.com:80

According to the spec: https://httpwg.org/specs/rfc7231.html#CONNECT and https://httpwg.org/specs/rfc7230.html#request-target

We would expect the DNS resolution to be offloaded to the proxy, and the CONNECT to look like:

CONNECT server.example.com:80 HTTP/1.1
Host: server.example.com:80

The expected behaviour matches what we currently do in our http_proxy policy, where no resolution is applied on APIcast.

The same should apply for request to the 3scale backend.