Middleware for timely and reliable data dissemination is a fundamental building block of the event driven architecture (EDA), an ideal platform for developing air traffic control, defense systems, etc. Many of these middlewares are compliant to the data distribution service (DDS) specification and they have been traditionally designed to be deployed on managed environments where they show predictable behaviors. However, the enterprise setting can be unmanaged and characterized by geographic inter-domain scale and heterogeneous resources. In this paper we present a study aimed at assessing the strengths and weaknesses of a commercial DDS implementation deployed on an unmanaged setting. Our experiments campaign outlines that, if the application manages a small number of homogeneous resources, this middleware perform timely and reliably. In a more general setting with fragmentation and heterogeneous resources, reliability and timeliness rapidly degenerate pointing out a need of research in self-configuring scalable event dissemination with QoS guarantee on unmanaged settings.