You do need a server component, Microsoft Office Communications Server to
make this product work.

The version that works on the public IM network is MSN Messenger.

"hsmlives" wrote:

> I recently installed communicator 2007 as part of my office professional plus
> suite, however, I cannot log into it. Do I need a server piece for this to
> work as well? Every time I click the sign in button it says "cannot sign in
> because the server is temporarily unavailable". How does it handle
> authentication?