问题
I am trying to connect to Apple's Push Notification servers and push some notifications. All connections attempts are timing out. Tried pinging the server gateway.sandbox.push.apple.com and gateway.push.apple.com and they are not reachable. Are these servers alive and reachable? Can any body validate that they are reachable? Is it a regional problem?
回答1:
I posted this question on the Apple forums but did not get any response. But, I figured it out myself after lot of experiments. Any requests to APNS, whether ping or connection requests, that are routed through proxies are filtered out in the transit and will never reach the APNS. This is probably done due to security concerns by the Apple guys. This means that any requests from your machines at your work locations will never go through as they are always routed through a proxy server. Any requests that sent through a direct internet connection without any intermediate proxies make it to APNS.
To test this you can tether your mobile 3G connection and share it with your PC/Laptop and then try connecting or pinging APNS and it should succeed. Your mpobile 3G connection is a direct internet connection. To get it working at your work locations ask your IT for a direct connection.
Update: It happened to be a firewall issue. Resolved after configuring the firewalls to allow connections to APNS range of IPs.
来源：https://stackoverflow.com/questions/13524971/ping-to-apns-not-returning