I need to expose Active Directory, or at least the address book functions on the internet for some mail clients and other devices. The standard response is to simply not or vpn in, however VPN isn't an option for us with some of the hardware devices.

A number collages expose their setups out to the internet so I'm assuming their has to be a safe way of doing it. Best option I've come up with to install a linux ldap host, then hourly sync over the relevant contact information however that seems like major overkill.