What action helps you reduce local network traffic when deploying a content caching server?

Using an MDM restriction to prevent content caching from being turned off for every user's managed Mac is an effective way to reduce local network traffic. Content caching allows frequently accessed content from Apple services to be stored locally on a network, which significantly decreases the need for multiple devices to download the same content from the internet. This centralized approach not only conserves bandwidth but also enhances download speeds for users within that local network.

When content caching is enforced through MDM restrictions, it ensures that all managed Macs consistently use the cache for downloading software updates, apps, and other content, thus minimizing redundant internet traffic. By keeping content caching enabled across devices, you create a more efficient network environment where resources are utilized optimally, leading to enhanced performance and reduced strain on the local internet connection.

The other options either do not directly impact the effectiveness of content caching or may not provide the same level of control and efficiency. For example, disabling VPN for users pertains to connectivity rather than optimizing local content delivery.