A method of collecting health check metrics for a network is provided. The method, at a deep packet inspector on a physical host in a datacenter, receives a copy of a network packet from a load balancer. The packet includes a plurality of layers. Each layer corresponds to a communication protocol in a plurality of communication protocols. The method identifies an application referenced in the packet. The method analyzes the information in one or more layers of the packet to determine metrics for the source application. The method sends the determined metrics to the load balancer.