I've been testing some recent functionality of ChatterEmail that connects it directly to Exchange via the DAV interface. Very slick. Even better, this interface supports push notifications.

Now comes the problem. We had this working piggybacking UDP 500, which Cingular apparently left open to support some VPN clients (it's the IKE port). But within the past two weeks, it's been closed... and more than a few of us aren't pleased. Anyone know why this happened, what might be done about it, or if there are potentially other UDP ports that *could* be used for notifications from Exchange back to the device?