You can do some pretty simple testing to Apple’s APNS of ports and network communications using strategies I’ve outlined in the past with tcpdump, trace route, telnet, curl, stroke and of course ping. These are classic ways to test connectivity to servers. However, netcat has a few interesting things you can do with it; namely actually run a port super-quickly to test traffic between subnets, forcing scans of ipv6 traffic, debugging sockets, keeping connections alive, parodying through SOCKS 4 and 5 and just checking for daemons that are listening rather than actually sending data to them.
Learn To Test Connectivity to Apple Push Notification Services Here…