Aside from the information provided by @franton that is unofficial, but easily reproducible and is really great and much thanks to him for doing all that hard work and sharing it. Does Apple provide an official white paper, support document, business.development document, etc. Where they present officially, what are the servers that live behind *.apple.com and/or at least document saying officially in order for APNS or DEP or whatever to work, the following addresses are critical.
It has been well documented that some businesses are ok with flipping the switch and allowing all 16,777,214 addresses in that space free reign from/to their networks, but there are also other places which due to federal compliance, regulation or good l'fashioned security, need a document stamped by Apple and deemed as official, that reproduces a portion of that spectrum or at least the parts relevant to each of the services.
It would server really well if they just grabbed @franton 's list and put the Apple Logo on it and made it official... I think a lot more businesses that use Apple would be more open to opening this ports...
It's been a couple of years now that Apple wants to publish how much they want to get in the Enterprise and how its leveraging this and that to make the Enterprise much happier with Apple, but its lack of attention to detail like this that makes Enterprise not really happy with them. Apple has not really stepped up and provided the much needed enterprise level documentation about what is available within that spectrum and Apple Engineers, Managers, and other higher level management don’t seem know if even such documentation exists or is available somewhere.
We shouldn’t have to guess on what their technologies contain, how do they exactly work from a security perspective. I wish someone from Apple read this and made some true effort in either making this documentation appear or provided it for everyone else that needs it.