iOS 15 introduced a new feature called Private Relay. This feature sends traffic between two different networks, anonymizing your traffic which prevents websites and service providers from seeing your IP address and location. Great for privacy, horrible for those that deploy network controls to create a safe browsing experience.
There are ways to disable Private Relay via the settings interface, but if you’re an enterprise managing a fleet of devices this might be challenging.
To help, if you are using the CleanBrowsing service you can now use the mobile.config files for MacOS and iOS to disable the feature.
The iOS / MacOS app does not currently disable this feature.