Here's an odd one. I've got my Time Capsule setup to distribute a dual-band network. Today I've spotted then when my iPad is connected to the 5Ghz network iMessage doesn't send or receive (have functioning internet, and Mail and Notes sync OK with iCloud). If I then connect the iPad to the regular 2.4Ghz network, after a minute the iMessages I attempted to send, send OK and I can receive also. I've found this out as my brother's iPad wasn't getting any messages from me (sitting in same room on same network but his iPhone was). iPhones 4S doesn't support 5Ghz, so that's connected to the 2.4Ghz network. Similarly, iMessages appeared on my iPhone but not on my iPad which I tested on 5Ghz. the MacBook Air on 5Ghz happily sends and receives iMessages. Any ideas why the iPads don't? Can anyone confirm/test this for me? Thanks.