Here is a thread from the past that might help: https://lists.cloudfoundry.org/g/cf-dev/message/4503

Mike

On Fri, Feb 16, 2018 at 3:50 AM, John Mcteague <john@...> wrote:

When a route is not found by the gorouter, clients receive a http 404, which can be confusing for some downstream clients as its hard to distinguish between the resource in my app is not found vs the entire app is not found.

502 bad gateway is used in CF when the route is known but it is temporarily unable to reach the app backend.

Is there any thought on changing the error the gorouter returns in this scenario to help provide clients more meaningful information.Checking the X-cf-routererror header (which returns unknown_route) is not desirable as this starts to bake in CF specific behaviours into applications.

Thanks,

John