What configuration change can an administrator make to allow access to Twitter while blocking all other social networking sites?

The most effective approach to allow access to Twitter while blocking all other social networking sites hinges on using the Static URL Filter to manage specific exceptions in web filtering. By setting the action to Exempt in the Static URL Filter configuration, the FortiGate device will bypass filtering for Twitter specifically, permitting user access to the site while still applying the restrictions to all other social networking sites.

This method is particularly beneficial because it allows for precise control over which URLs are exempt from filtering while maintaining a comprehensive block on the rest. By strategically utilizing exemptions, an administrator can tailor web access based on organizational needs without needing to completely disable web filtering, which would render all sites accessible and undermine security policies.

Other methods in the choices provided might not accomplish the desired outcome effectively. For instance, setting Action to Allow in a URL filter may permit access selectively but could lead to unintended access to other sites unless carefully managed. Similarly, adding Twitter to Allowed Sites could also result in broader permissions than intended, as it may not block similar social networking sites without careful configuration. Disabling the Web Filtering Profile altogether would remove any restrictions on all sites, conflicting with the original goal of blocking everything except Twitter.