We,ve just been quoted $5000 for Zimbra!! Am I looking in the wrong place as M$ would only cost around £250 a year on our schools agreement.
I really can't get on with the webmail, I agree everything is there you need and it's very robust but the interface is dire and its use of IMAP seems flakey to me, too many users problems seting up up folders etc..! Also and more importantly no macs in school can run through its proxy or filtering, just refuses to accept the password. The Navaho support I have to say leaves me cold and they have also declared the box obsolete now.
I'll investigate the filtering software suggested by everyone, thanks
Simon