AlertNet is a decentralized, zone-aware safety alert system designed for the Internet of Vehicles (IoV). It addresses the critical need for rapid, trustworthy hazard information exchange between vehicles without relying on a single point of failure. The system creates a hybrid architecture by coupling cloud-based geofencing with per-zone Ethereum smart contracts. This allows drivers to receive tamper-evident, locality-specific alerts (such as accidents or road hazards) in real-time. The solution features a mobile perception layer for drivers, a serverless network layer for efficient routing, and a blockchain application layer that ensures the provenance and immutability of every safety report.