Fault injection is an efficient technique to evaluate the robustness of computer systems and their fault tolerance strategies. In order to obtain accurate results from fault injection based tests, it is important to mimic real conditions during a test campaign. When testing dependability attributes of network applications the real faulty behavior of networks must be closely emulated. We show how probability distributions can be used to inject communication faults that closely resemble the behavior observed in real network environments. To demonstrate the strengths of this strategy we develop a reusable and extensible entity called FIEND, integrate it to a fault injector and use the resulting tool to run test experiments injecting non-uniform distributed faults in a network application taken as example.