A multi-site network is a group of linked locations that operate as one organization and may share systems, data, or identity controls. In healthcare, that can mean common email, scheduling, imaging, records, file storage, and authentication across multiple clinics or offices.
This matters in cyber security because a compromise at one site can spread across the others if the network is poorly segmented or if shared accounts and services are exposed. Attackers often look for these shared dependencies to increase leverage in ransomware or extortion campaigns. Defenders reduce risk by isolating critical systems, using strong access control and MFA, limiting trust between sites, and testing whether one location can be contained without disrupting the whole organization.