Zimbra is an open source server and client technology for next-generation enterprise messaging and collaboration. Zimbra delivers innovation for both the administrator and the end-user as well as compatability with existing infrastructure and applications (both open source and proprietary). Zimbra is open source in order to leverage the collective talent of the greater community, and to ensure investment protection for Zimbra partners and end-users.
Could we replace Exchange server with Zimbra? Perhaps, but since Zimbra is only in beta and an Exchange server license we would use for four years will cost us about $2,000, I’m not yet prepared to take the plunge.