Which type of network is not accessible from outside the organization by default?

The type of network that is not accessible from outside the organization by default is an intranet. An intranet is a private network used internally within an organization, typically designed to facilitate communication, collaboration, and information sharing among employees. Access is restricted to authorized users, which means outsiders cannot access its resources or data without permission or specific access provisions.

This characteristic distinguishes intranets from other types of networks. For instance, the Internet is a vast global network that is openly accessible to the public, and an extranet is a controlled private network allowing outside users to access certain information while still being part of an internal environment. A Local Area Network (LAN) is a smaller network that connects devices within a limited area, such as a single office or building, and can include both internal-only and publicly accessible segments depending on its configuration. Therefore, the nature of an intranet with its internal focus makes it the correct answer to the question.