To use Apple Push Notification service (APNs), you need a direct and persistent connection to Apple's servers. Your device connects to APNs using cellular data if it's available. If there's no viable cellular connection, the device switches to Wi-Fi.
If you use Wi-Fi behind a firewall or a private Access Point Name (APN) for cellular data, you'll need a direct, unproxied connection to the APNs servers on these ports:
- TCP port 5223: For communicating with Apple Push Notification services (APNs)
- TCP port 2195: For sending notifications to APNs
- TCP port 2196: For the APNs feedback service
- TCP port 443: For a fallback on Wi-Fi only, when devices can't reach APNs on port 5223
The APNs servers use load balancing, so your devices won't always connect to the same public IP address for notifications. It's best to allow access to these ports on the entire 184.108.40.206/8 address block, which is assigned to Apple.
APNs stands for the Apple Push Notification service. APN stands for Access Point Name, the gateway between a cellular data network and the Internet.