By default, Exchange Server 2010 and Office 365's Exchange Online service will allow any ActiveSync-compatible device to connect to your Exchange infrastructure. This includes Windows Mobile, Nokia, Android, and iOS devices among many others.
If you're planning on supporting a selected number of iOS devices you may wish to restrict the device types that can connect with the option, to either completely block or quarantine devices that don't meet the criteria chosen.
As an example, we'll look at how to enforce criteria to:
Only allow iPhone devices
Quarantine any other devices that connect
Inform an administrator of quarantined devices
Before we set up these criteria, as a pre-requisite, connect a test device of the type you wish to be able to allow. This will populate Exchange with information about the device type so it can be chosen when creating a rule.
The most straightforward way to accomplish this is using the Exchange Control Panel, navigating to Phone & Voice...