Which feature allows administrative control over user access to the internet through ProxySG?

User authentication is the feature that enables administrative control over user access to the internet through ProxySG. By utilizing user authentication, administrators can require users to log in with their credentials before they are allowed to access the internet. This ensures that access can be controlled, monitored, and restricted according to the organization's policies.

With user authentication, administrators can create rules based on user identities, group memberships, or roles, allowing for customized access levels. For example, certain users might be granted unrestricted access, while others might only be allowed to visit predefined websites. This level of control is essential for maintaining security and compliance within an organization.

In contrast, while content filtering restricts access to specific types of content based on categories or keywords, it does not inherently require user identity verification. Traffic shaping manages bandwidth and optimizes application performance rather than controlling access. Load balancing distributes network traffic across multiple servers to enhance performance and reliability, but it is not related to user access control.