Controlling access to your mailserver can be a bit of a hassle. We have therefore implemented that only ActiveSync devices (aka Mobile Devices) can connect to our Exchange server(s) from the internet.
Each device requires that access is being granted to the device before proceeding. A relatively simple way to prevent someone random from setting up an e-mail client from an unknown device.
Is there a similar way, and add-on or something that can control Outlook Clients? Since Outlook is not using activesync and is not treated as a mobile device, you cannot manage access AFAIK.