Formal methods to verify authentication in TACACS+ protocol

Modern routers provide services such as authentication, authorization and accounting facilities for networking which are essential for any network. Routers use various family of protocols to achieve the required level of service what user requires. Services such as virtual private network service across networks enable users to communicate privately and securely. Commercial routers support the AAA services using TACACS+ and RADIUS protocols. In this paper we present a novel frame- work for verifying authentication Protocol such as TACACS+ which helps to set-up a Virtual Private Network in routers.