Systems and methods for implementing a cooperative security fabric (CSF) protocol are provided. According to one embodiment, an NSD of multiple NSDs participates in the dynamic construction of a CSF interconnecting the NSDs in a form of a tree, having multiple nodes each representing one of the NSDs, based on hierarchical interconnections between the NSD and directly connected upstream and downstream NSDs. A communication channel is established by a backend daemon of the NSD with a directly connected upstream node of the NSD within the CSF through which queries and replies are communicated and through which periodic keep-alive messages and responses are exchanged between the upstream node and the NSD. A CSF protocol is enforced by a forward daemon of the NSD that limits issuance of query messages to those originated by a source NSD representing an upstream node and directed to a destination NSD representing a downstream node.