IIS has been supporting reverse proxy configuration since URL Rewrite and Application Request Routing modules were released a few years ago. It is possible to configure an IIS hosted web site to act as a reverse proxy and forward web request to other URL’s based on the incoming request URL path. This is described in details in Reverse Proxy with URL Rewrite v2 and Application Request Routing.
Not too many people know however that the same kind of configuration can be achieved with a web site hosted in Azure Web Sites. This blog post explains the configurations steps to enable that.
Read the complete post here