CHAPTER 24 Formal Analysis of Policy-Based Security Configurations in Enterprise Networks 605 address the dynamic changes in network topol- ogy during this verification process. Moreover, the dependencies between various network ser- vices must be analyzed where these dependen- cies may introduce some implicit/hidden service access path in the network, which may in turn violate the organizational security policies. The next section describes a verification framework for analyzing policy-based security implementa- tions in enterprise networks. 24.3. FORMAL VERIFICATION OF SECURITY POLICY IMPLEMENTATIONS In this section, a formal verification framework has been presented for analyzing the distributed security policy implementations in enterprise net- works. The proposed verification framework [1, 21] primarily focuses on the following issues: different nodes (source and destination) in the network. The complexity of the security policy depends on the size of the network, number of controlling parameters, and dependency amongst the rules. Researchers have reported that the policy specification language must be expressive enough to represent complex security constraints of the network correctly. As a part of the ver- ification framework presented in this chapter, a simple network security policy specification lan- guage, namely NSPSL, has been proposed in this section. Network Security Policy Specification Lan- guage (NSPSL). The main constructs of the NSPSL can be classified into two categories: (a) network topology constructs and (b) network ser- vices and policy rule constructs. Network Topology Constructs. The pro- posed NSPSL language has the following con- structs to describe the network topology.