The Zero-trust network model is designed to ensure strict identity verification for every user or device attempting to access network resources, regardless of whether they are inside or outside the network perimeter. This model operates on the principle of "never trust, always verify," which means that no one is trusted by default, and verification is required from everyone trying to gain access to resources on the network. On the other hand, the Castle-and-Moat model operates on the principle that once inside the network, users or devices are generally trusted. This model does not enforce strict identity verification for every user or device within the network, which is a fundamental difference from the Zero-trust model.