Abstract—The security mechanisms employed in current networked environments are increasingly complex, and their configuration management has an important role for the protection of these environments. Especially in large scale networks, security administrators are faced with the challenge of designing, deploying, maintaining and monitoring a huge number of mechanisms, most of which have complicated and heterogeneous configuration syntaxes. Consequently, configuration errors are nowadays a frequent cause of security vulnerabilities. This paper summarizes results from a doctoral thesis that offers an approach to the configuration management of network security systems specially suited to the needs of the complex environments of today’s organizations. The approach relies upon policy-based management and model-based management, extending these approaches with a modeling framework that allows the design of security systems to be performed in a modular fashion. The model is segmented...