What is the function of the proxy auto-configuration (PAC) file?

The proxy auto-configuration (PAC) file serves a specific functional role in directing web traffic, making the correct answer relevant to its core purpose. A PAC file contains JavaScript code that defines how web browsers and other user agents can automatically choose the appropriate proxy server for fetching a given URL. By outlining the conditions and rules for routing web requests through a proxy, it facilitates flexible and efficient network management.

In a FortiSASE context, the PAC file becomes pivotal by allowing organizations to specify which traffic should be handled by the FortiSASE proxy, thus enabling secure web access and policy enforcement based on the organization's needs. This capability ensures users are routed through the necessary security measures without needing to manually configure proxy settings on each device, leading to improved operational efficiency and security posture.

The other options pertain to functions that are not related to the primary operations of a PAC file. For example, user permissions and access control are typically managed through a different set of tools or systems, and automated software updates for security features are handled through update management processes rather than a PAC file. Additionally, monitoring network bandwidth usage involves analytics and reporting tools separate from the function of routing web traffic.