Q. When using Azure AD Application Proxy do I need an on-premises agent for every application I publish or can the agents be shared?
A. When publishing applications externally using Azure AD Application Proxy an agent is deployed on-premises which provides the connectivity between on-premises and Azure. This allows the applications on-premises to be published externally. The agent that is deployed is used for all published applications and is not affinitized to a specific application. If you deploy multiple agents on-premises they will be used in a round-robin type fashion to publish the applications to provide for scale and high-availability. It is currently not possible to restrict specific agent deployments to publish only certain applications. The agents will always be used for all published applications.