Alternatives to Postfix


One of the last areas where Microsoft has yet to be surpassed by an open-source product is in the area of corporate groupware and messaging. Many businesses use Microsoft Outlook and/or Microsoft Exchange Server to get email, provide calendaring, notes, file sharing, and other collaborative functions. General industry complaints about Exchange Server abound, and they center on issues of scalability, administration (especially backup and restore, where there is a thriving third-party market), and licensing fees.

A "drop-in" alternative needs to have compatibility with Outlook because it's intended to replace Exchange Server in an environment where there are Microsoft desktops in existence using Outlook. A "work-alike" alternative provides similar features to Exchange Server, but does not offer compatibility with the Outlook client itself; the latter is typical of many of the open-source alternatives.

There are several drop-in alternatives, none of which are fully open source because some type of proprietary connector is needed to provide the services to Outlook clients (or provide Exchange services to the Linux Evolution client). For Outlook compatibility, the key seems to be the realization of a full, open implementation of MAPI, Microsoft's Messaging Application Program Interface. That goal is going to be difficult to achieve because MAPI is a poorly documented Microsoft protocol. For Linux-only solutions, the missing ingredient for many alternatives is a usable group calendaring/scheduling system similar in function to that provided by Exchange Server/Outlook.

Of course, independent applications for these functions abound in the open-source world, but one characteristic of groupware is its central administration; another is that all components can share information.

Central to the open-source challenge to Microsoft's dominance in this area is the move toward open standards for messaging, calendaring, and scheduling. The Calendaring Distributed Authoring and Versioning (CalDAV) standard is based on earlier work on distributed authoring and versioning on the Web (WebDAV). With a more orderly, standards-based approach, Exchange's days of dominance may be numbered.

The following sections examine several of the available servers, beginning with Exchange Server itself and moving toward those applications that have increasing incompatibility with it.

Microsoft Exchange Server

Exchange Server and Outlook seem to be the industry benchmark because of their widespread deployment. They offer a proprietary server providing email, contacts, scheduling, public folders, task lists, journaling, and notes using Outlook as the client and MAPI as the API. If you consider what Exchange offers is the "full" set of features, no other replacement offers 100% of what Exchange does.

CommuniGate Pro

CommuniGate Pro is a proprietary, drop-in Exchange alternative, providing email, webmail, LDAP directories, a web server, a file server, contacts, and a list server. The CommuniGate Pro MAPI Connector provides access to the server from Outlook and other MAPI-enabled clients.

Novell GroupWise

GroupWise is Novell's proprietary messaging and calendaring solution. Besides email, it handles instant messaging and task and document management. For the first time, a GroupWise client is being included in SUSE Linux 10.

Samsung Connect

This is a proprietary, drop-in Exchange alternative. The Samsung Connect server provides what is almost a full replacement for Exchange and will support whatever calendaring standards finally emerge to support Linux.

OPEN-XCHANGE

OPEN-XCHANGE was SUSE's attempt to enter the groupware market prior to being acquired by Novell. Built mainly around Java-oriented components, OPEN-XCHANGE offers a web-based interface that handles contacts, calendaring, email, and task management. It is based on Cyrus IMAP and Postfix. Working with SUSE Linux Enterprise Server (SLES), OPEN-XCHANGE can also do project management, forums, and bookmarks.

Kolab/Kroupware

The Kolab initiative began when a German state government approached the KDE developers' group with some funding for a groupware solution. Kolab2 uses Postfix, Cyrus-imap, OpenLDAP, and ProFTPd as its open-source core, and it works best with the Kontact client.

OpenGroupware (Ogo)

Formerly SKYRiX, OpenGroupware provides groupware and collaboration pieces to any existing email configuration. It provides calendaring, contacts, webmail, task management, resources, and projects and document management. It runs on the SOPE application server.

phpGroupWare

This may be the best known of several projects based on PHP, which you will learn more about in Chapter 31, "Creating Dynamic Websites." Others include PHProjekt, eGroupware, and more.groupware. It is used with a database management system such as MySQL or PostgreSQL, plus a web server and an IMAP mail server. It provides a web-based calendar, a task list, an address book, email, and it throws in news headlines and a file manager for grins. The problem is that phpGroupWare doesn't really function outside of a browser, leaving the field to more robust clients.

Hula

Yet another Novell open source initiative, Hula began its life as a proprietary NetMail server. NetMail was open-sourced in spring 2005, and its initial development team spoke openly of rethinking the way people collaborate and making Hula the application to support the ways that people really work. Its stated goal is "to be fun and easy to use, while scaling effortlessly from small groups to large organizations with thousands of members." At the time of this writing, however, version 1.0 was still a ways off.

Conclusion

As stated earlier, corporate email will not likely change dramatically until an alternative standard is developed. That will likely come out of the discussions at the Internet Engineering Task Force in the coming years. Until then, businesses can and should try some of the existing open-source products, knowing that when the standards arrive, their business will be ready.



SUSE Linux 10 Unleashed
SUSE Linux 10.0 Unleashed
ISBN: 0672327260
EAN: 2147483647
Year: 2003
Pages: 332

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