exchange server alternatives

["Diego Cibils" <diego cibils adinet com uy>]

Hi all,

Does anyone knows, if there's any attemp out there to make a MS Exchange Server-compatible Mail/Groupware server ?
I mean, something like (Open)Exchange Server, that implements the Exchange protocol.

I guess it's a closed protocol, but perhaps, someone has tried to get into it !

Thanks,
Diego.