Zimbra™ Open Source Software

Zimbra is contributing its core intellectual property (IP) in enterprise messaging and collaboration to the Open Source Software (OSS) community. Zimbra is making the contribution in the hopes of:

  1. Getting our technology into the hands of as many users and developers as possible;
  2. Validating and enhancing our architecture and implementation through the OSS community;
  3. Driving down costs for and protecting investment in the deployment of collaboration/messaging technology;
  4. Giving back to the community that provided so much technology that we leverage within Zimbra - Linux™, Apache™, MySQL™, Postfix™, OpenLDAP, and so on; but at the same time.
  5. Building a profitable business (a.k.a., funding future investment) through the selling of optional "network" services to those users that choose to become customers as well.

What have we open sourced? The following capabilities are included in the open source software of the Zimbra Collaboration Server, which is available for download in both source and (unrestricted) binary formats:

  • All collaboration functions - email, group-scheduling calendar, contacts, etc.
  • AJAX (Asynchronous JavaScript and XML) collaboration client compatible with Firefox, IE, and Safari
  • Support for IMAP and POP Email clients (Outlook/Entourage, Apple Mail, Thunderbird, etc.)
  • Support for calendaring clients (Apple iCal, Sunbird)
  • Support for Internet Explorer and Firefox (with Safari support coming soon)
  • AJAX administrative client to provision, monitor, and manage collaboration services, servers, class of service policies, and underlying components
  • Unrestricted deployment in terms of number of clients, mailboxes, servers, and so on
  • Automatic indexing
  • Comprehensive search
  • Transactionally-managed operations (automatic redo logs that assure fault-tolerance)
  • AMAVSD integration for supporting the top Anti-Spam and Anti-Virus solutions from 3rd parties including SpamAssasin™ and Clam Anti-Virus
  • Privacy for network communications via SSL/TLS
  • Single-sign on with LDAP-compliant directories (including ActiveDirectory)
  • Integration with Postfix, MySQL, and OpenLDAP (all of which are embedded within the Zimbra Collaboration Server)
  • GAL and Authentication against ActiveDirectory

Why MPL? We chose the Mozilla Public License (MPL) for Zimbra's source and binary code offerings because:

  • MPL is one of the fastest growing OSS licenses — Participants in the Firefox community, for example, have already accepted it.
  • MPL guarantees end-user freedoms — Under MPL, end-users are free to share, deploy, and integrate derivative works of Zimbra throughout their organizations as well as within their IT outsourcing partners without any obligation to open source any value-added IP. And of course, enterprises can deploy the Zimbra Collaboration Server binaries for an unlimited number of users with no requirement to have a commercial relationship with Zimbra, Inc.
  • MPL encourages third-parties to provide value-added components — Any vendor is free to produce, integrate and sell separable open- or closed-source extensions to the Zimbra Collaboration Server. We at Zimbra welcome value-add, particularly in the such areas as workflow, commercial anti-spam & anti-virus, and application programming interfaces (Java, PHP, Python, C/C++, .) for binding to the XML endpoints within the Zimbra Collaboration Server.
  • MPL best ensures that value-added resellers do the right thing — Any vendor is free to use Zimbra's open source software to produce and sell a value-added derivative work of Zimbra such as
    • An alternative collaboration software product;
    • An email or collaboration appliance; or
    • A hosted email/collaboration service (in which a derivative work of Zimbra's AJAX client is inherently redistributed via browser-download to their customers (in both source code and, as appropriate.))
    provided that vendor either (a) makes their complete derivative work of Zimbra available in open source under the MPL and includes the proper attribution (in both source code and user interface), just as Zimbra, Inc. has done, or (b) enter into an appropriate commercial licensing relationship with Zimbra, Inc.

Zimbra Network™. Zimbra, Inc. will offer a subscription-based network for customers interested in certified binary releases, product support (either 5x10 or 7x24 coverage via phone, email, IM, etc.), stronger warranty, alerts, and maintenance/updates (i.e., enhancements and bug fixes in the form of backward-compatible, quality-assured new releases, patches, and service packs). The Zimbra Network is much like the models employed by other OSS companies such as Red Hat™.

The Zimbra Network will also include optional services that rely on closed-source software. All closed source components of the Zimbra network either:

  1. Are provided by 3rd parties, and for which there is no directly comparable OSS offering today;
  2. Are provided by Zimbra, but which directly incorporate proprietary intellectual property/software from 3rd parties; or
  3. Are provided by Zimbra, but which are (a) cleanly-separable, value-added extensions on top of the Zimbra OSS offering and (b) which are relevant to higher-end commercial deployments. Examples include tools for cross-mailbox search/discovery for Sarbanes-Oxley compliance, application-level replication for multi-site disaster recovery on commodity hardware, and so on.

Any closed-source components of the Zimbra Network may be replaced over time by open source components from third parties, from the Zimbra Community, or from Zimbra, Inc. Members of the community are welcome to contribute OSS components (and post them within the Zimbra Community) that provide similar functionality to that offered within the Zimbra Network. Finally, the core capabilities of the Zimbra Collaboration Server are not and will not be dependent on the Zimbra Network, and hence there is and will be no end-user requirement to subscribe to the Network.