Client computers in enterprise networks have the potential to be the source of serious security problems, especially when their hardware and software components are out of physical administrative control. Besides, services in the network may have client configuration requirements. We propose a system composed of a policy management and enforcement server and client agents, which authenticates the client users and checks their computer configurations before allowing their access to services. The information modeling within the design is based on Common Information Model. Web services are used for communication, following the related specifications in Web Based Enterprise Management.