Design a Distributed Blocking/Denylist System

Design a distributed denylist system that blocks requests from specified entities (users, IP addresses, emails, etc.). The system should integrate with external APIs to fetch blocked entity lists, handle both IPv4 and IPv6 addresses where applicable, support region-specific blocking rules, and efficiently propagate updates across a global infrastructure. Requirements include high availability, low latency lookups, real-time updates across multiple nodes, and the ability to handle government-mandated blocking scenarios.