What method is used to define permissions on a network or file but does not segment like VLANs or physical segmentation?

Access control lists (ACLs) are indeed the method used to define permissions on networks or files without the need for segmentation like VLANs or physical separation. ACLs are a set of rules that allow or deny access to resources based on various attributes such as user identity, IP addresses, and protocols.

This method is crucial in enforcing security policies by controlling which users or systems can access specific resources within a network. For instance, an ACL can permit a specific user to read a file while preventing others from accessing it entirely. This functionality is essential for safeguarding sensitive data while still allowing authorized users to perform necessary tasks.

VLANs and physical segmentation focus on separating traffic and restricting access through different network paths or infrastructure setups, making them less effective for managing access at the level of individual resources. Transmission control, while important for managing data flow in networks, does not deal with permissions or access rights for users or systems. Access control lists therefore provide a more direct and targeted way to manage permissions, enhancing fine-grained control over access in a network environment.