Modeling and Simulation (M&S) is one of the most multifaceted topics present today in both industry and academia. However, we are involved in a new M&S paradigm. Systems are becoming more complex and new simulation needs arise and have to be studied. As a consequence, the way in which we perform M&S must be adapted, providing new ideas and tools. In this paper, we propose a rule-based constraints evaluator, which facilitate the validation and verification of complex models in a transparent manner. For this, constraints are defined. The constraints definition process is completely independent of the model development process because (a) the set of constraints is defined once the model has been developed, and (b) constraints are validated at simulation time. The proposed Constraint M&S architecture has been built using the Discrete Event System Specification (DEVS) formalism and has been tested on a validated data center simulation model.