I've heard bits and pieces about other open source exchange replacement options out there, but I've never looked into them too extensively. Well, our Exchange server has been down for days and multiple tech engineers are looking into it around the clock and it seems to be that the problem is exponentially bigger than anyone anticipated.
As a result, I can't help but to wonder why bother. At this point (if it were me calling the shots) I'd be considering another option while you're going to have to build from ground up.
Has anybody used any open source exchange solution? I've heard a lot about Zimbra, but as I said I've never messed with anything else.
Just wanted some constructive thought on this field. Thanks!