Peer-to-Peer (P2P) is a flexible architecture that let a network grow up in an arbitrary way by adding more and more peers providing resources to the whole system. If uncontrolled, however, this growth might lead to stability and reliability problems, due to the fact that any host might join the network, no matter whether it may provide guarantees or not. Another problem that might occur is the difficulty to administrate the network due to its possibly uncontrolled growth and its frequent topological changes. This paper focuses on the description of an approach to administration?s automation based on the systematic use of policies. The goal is achieved by means of evaluation of the resources owned by each host, which addresses the problem of provision od reliable resources too. We believe this is a good solution to both problems. In this paper we will explain how our approach works and the benefits rising from its use. In order to better test our approach we developed and tested a working prototype of the system, also described in this paper.