Can we safely assume that App Store server notifications will originate from 17.0.0.0/8 address block?  More specifically, does the Technical Note TN2265 - https://developer.apple.com/library/ios/technotes/tn2265/_index.html#//apple_ref/doc/uid/DTS40010376-CH1-TNTAG41 about push notifications also apply for App Store server-to-server notifications? The IP address range for the push service is subject to change [...] However, the entire 17.0.0.0/8 address block is assigned to Apple, so you can specify that range in your firewall rules