My office has several designers who use Macintosh computers. Can the Macs use Exchange 2000 Server Instant Messaging (IM)?

Two separate, but related, IM protocols exist in the Microsoft world: Exchange 2000 IM uses the rendezvous protocol (RVP), and MSN Messenger uses a proprietary protocol. These two protocols differ enough that they aren't directly interoperable. The Windows Messenger client that ships with Windows XP and the Exchange IM client that comes with Exchange 2000 feature a plug-in architecture that can support more than one IM protocol. That's why you can use Windows Messenger to sign on to both Exchange 2000 IM and MSN Messenger. Unfortunately, the otherwise excellent MSN Messenger client for Mac OS doesn't support Exchange 2000 IM. If you need this feature, you might consider sending an email message to If Microsoft receives enough requests, perhaps it will add support for Exchange 2000 IM in a future release.