Abstract. We consider monitoring and checking formally specified properties in a network. We are addressing the problem of deploying the checkers on different network nodes that provide correct and efficient checking. We present the DMaC system that builds upon two bodies of work: the Monitoring and Checking (MaC) framework, which provides means to monitor and check running systems against formally specified requirements, and declarative networking, a declarative domain-specific approach for specifying and implementing distributed network protocols. DMaC uses a declarative networking system for both specifying network protocols and performing checker execution. High-level properties are automatically translated from safety property specifications in the MaC framework into declarative networking queries and integrated into the rest of the network for monitoring the safety properties. We evaluate the flexibility and efficiency of DMaC using simple but realistic network protocols an...