Advanced routing capabilities using Application Gateway Rewrite Rules

Thanks for the great question rashmitripathi. Checking DNS is not possible, but I assume the intention here is to inject the correct authorization header based on the backend the request was being sent to. If that is the case, you could follow the above steps to establish the multiple backends and rewrite sets, and expand the rewrite sets with an additional rule that adds the matching header.

As each backend is represented by a dedicated path-based rule, and each path-based rule is associated to a dedicated rewrite set, this rewrite set can be used to inject any necessary headers required by the backend. Here is an example of setting the Authorization header as a second rule after stripping the path prefix that is temporarily injected to steer to the desired backend:

Hope this helps.