C2s

C2S is an acronym that can refer to several concepts depending on the domain. In information technology, it most often appears in two forms. As "Client-to-Server," C2S denotes the direction of communication in a client-server architecture where clients initiate requests to a server which processes them and returns responses. This framing helps describe API interactions, web services, and distributed systems where the client is the initiator of the exchange.

In cybersecurity, C2S commonly stands for "Command and Control Server." A C2S is a remote server that operators of malware, botnets, or other malicious campaigns use to issue commands, receive data, and coordinate infected devices. Defenders monitor for C2S traffic, looking for beaconing, unusual outbound connections, or known command-and-control infrastructure, and may seek to disrupt or dismantle such servers.

Other, less standardized uses of C2S exist in fields such as business process naming (for example, client-to-service workflows) or domain-specific jargon. Because acronyms can be ambiguous, the intended meaning of C2S should be inferred from the surrounding context.