Q: OSX Caching Server not caching IOS downloads

I have moved my caching server from one site to another. It was working fine at the first site.

I have gone over and over all settings, DNS etc and everything appears correct.

The Caching Server will cache download performed on itself from the AppStore. So the caching server is online. Any IOS download or update I perform from multiple devices does not download via the Caching Server. Regardless of which device or how many times I restart them or check settings it just won't cache downloads from these devices.

The network setup is a little unusual in that there is one IP address for inbound traffic and another IP address for outbound traffic. Both the inbound and outbound addresses are configured in the Caching Servers Permissions. I cannot see any errors in the Caching Server Logs. The devices and the OSX Server are on the same IP subnet. There is no firewall between devices on that subnet etc. Cache used = 253.5MB on an otherwise empty 750GB Drive.

Any advice on why it is not working?