To resolve this issue, you might allow all Apple devices shipped with free software to act as an Apple cache by enabling the feature on the device that will be left on all the time. When an update is released, all Apple devices on the network are automatically directed by Apple to download the update from the local Apple cache. Each update is downloaded from Apple only once, which minimises the impact on the Internet connection.

However there could be some issues affected by implementing the Apple cache.

The device that acts as the Apple cache registers itself with Apple. Apple associates the public IP address with that particular cache. When an update request arrives from the same public IP address, Apple sends a message back telling the device to fetch the update from the local cache.

For example, we have ten proxy servers in our proxy farm. If school A sets up an Apple cache and when it registers with Apple the request just happens to be sent through proxy seven, Apple will associate the public IP address of proxy seven with that Apple cache.

Then an Apple device from school B checks for an update. The request just happens to be sent through proxy seven. Apple recognises the public IP address and tells the device to go and fetch the update from the local cache. But the local cache is in school A and our firewall prevents the device from reaching the cache. So any device that happens to be directed through proxy seven will be unable to obtain any updates from Apple (unless it is in the school that actually has the Apple cache).

To ensure that updates from Apple continue to work, we are currently preventing all schools from hosting an Apple cache. This is achieved by preventing any Apple cache from registering with Apple.

If your school wants to run an Apple cache then the only way to make it work is if all traffic sent to Apple bypasses our web filtering. Then we can ensure that all devices in the school are hidden behind the same public IP address and that the IP address is unique to that school.

If the school has RM broadband and is using an Apple cache, then they can contact the service desk on 0845 404 0000 so we can implement a workaround as mentioned above.