As software systems evolve by adding new extensions some unexpected conflicts may occur, which is known as the Feature Interaction Problem (FIP). FIP is a threat to the dependability of software systems as it can break system security and safety. A major cause for FIP is the non-determinism related with sending or receiving the predefined signals of the base subsystem by extensions. This paper analyzes the problems and proposes to enforce necessary constraints to prevent the FIP. In addition, we present a systematic approach to acquire heuristically constraints from system specifications.