|  |  | Cisco routers provide integrated firewall and intrusion detection functionality for the perimeter of the network. available for a wide range of Cisco IOS software-based routers offers security and policy enforcement for both internal to internal and internal to external connections The Firewall Feature set: available as a security-specific add-on option for existing IOS software adds enhanced security capabilities such as authentication, encryption, and fail-over provides application-based filtering (context-based access control), defense against network attacks, per-user authentication and authorization, and real-time alerts.