Modern network infrastructures require high speeds for multiple services at once and a robust defence against cyber threats. Among these, Denial-of-Service (DoS) attack is a major risk because it consists of flooding systems to make them unavailable. The security provided by conventional firewalls using static rules becomes insufficient when networks experience this type of attack. To address this limitation, this thesis develops a framework that combines verified static configurations with flexible runtime rule distribution. The system integrates VEREFOO (Verified Refinement and Optimized Orchestrator) which generates optimized and formally verified firewall policies at design time with REDIAL (RulE DIstribution ALgorithm) which operates at runtime to distribute rules between cascaded firewalls.