Volume Number: 25
Issue Number: 12
Column Tag: New Tools for Collaboration

New Tools for Collaboration: Alternatives for Exchange

"Exchange for change," or, "Implementing Exchange Server services without the Exchange Server price."

by William Smith

As much as Mac enthusiasts may like to dog Microsoft, it does have a strong influence in the E-mail and collaboration world. That's not because Microsoft dominates the enterprise market but because its Exchange Server product (http://www.microsoft.com/exchange) is scalable, reliable and feature-rich. A little more than a dozen years old, Exchange Server has morphed from its predecessor Microsoft Mail, which worked over a LAN with clients connecting to file servers, into a suite of tools that not only let co-workers collaborate in the office but extends their offices to the Internet and mobile devices.

Exchange Server was not the first E-mail server. It was not the first to include a calendar, was not the first to offer type-ahead addressing from an address book and was not the first to extend itself through webmail. It has, however, incorporated these features and many more from its kin into a robust system that millions of users today consider fundamental to their work. Today, other collaborative messaging systems—those with features beyond basic mail—compare themselves to Exchange Server in their marketing and advertising. It has become the gold standard.

For many reasons, though, Exchange Server isn't for everyone. It runs only on a Windows Server. It requires Microsoft E-mail clients to get the full Exchange experience. It's not simple to administer. It's not cheap.

So, what's the alternative?

In 1962, the Avis car rental company debuted its "We try harder" campaign, which featured a no-nonsense slogan explaining it wasn't the leader in the industry and it knew it. That mentality still hits close to home with many people and its one of the reasons why entrepreneurs still try to compete with Microsoft and why customers will often avoid the big name brand in favor of the "little guy".

A few companies have jumped onto the collaborative messaging bandwagon and directly bill themselves as alternatives to Exchange Server. Two well-known contenders are Kerio and Zimbra, which will be discussed in more detail shortly. Other alternatives are available but Kerio and Zimbra are well established and represent different target markets within the Exchange alternatives group.

A talk about collaborative messaging wouldn't be complete without mentioning both Novell GroupWise and Lotus Notes with Domino server. Both of these products are in direct competition with Microsoft Exchange Server, however, they are existing enterprise solutions with their own footholds of supporters. The purpose of this article is to offer ideas for ways to look at alternatives to Exchange that are targeted toward smaller organizations and those on tight budgets.

Today's current buzzword to describe Exchange is "collaborative messaging". 10 years ago it was "groupware". These are simply terms used to describe the ability to work with others and share information electronically.

At the heart of collaborative messaging is the electronic trinity—mail, calendaring and contacts. These three services go hand-in-hand to help the end-user transfer data, coordinate with others and maintain relationships.

Figure 1. The electronic trinity

Some might consider a fourth service, Tasks, to be considered fundamental to their workflows for tracking progress. For now, though, only mail, calendaring and address book have standard transfer protocols that allow their data to move between disparate systems. Mail has the MIME format, calendaring has the iCalendar format and the address book has the vCard format. Sending and receiving tasks between server systems is still not commonplace and in many cases simply not possible.

Any fundamental Exchange Server alternative must support these three basic services. Otherwise, it is simply another mail server.

Collaborative messaging is more, though, than just these three services running on a server. Collaboration also requires being able to access data in real time. For example, users must be able to share their calendars so that others can schedule meetings with them or simply know when they are available. They must also be able to trust that phone numbers updated by a co-worker in the office are correct on their mobile phones.

These three basic services must be available on demand and on a variety of platforms. Mobility and portability are key! A desktop client application such as Microsoft Entourage will offer a rich collaboration experience in the office but is useless when a project manager only has five minutes between meetings in the next building. His mobile device must serve as his client application. When he's vacationing, but still needs the ability to respond to critical messages, a web browser on the hotel kiosk computer can provide yet another avenue for both accessing and contributing real-time data.

Figure 2. Messaging via web browser, mobile device or desktop client in real time

Exchange Server can be expensive to license and maintain. It requires server hardware, a Windows Server operating system license, Exchange Server license, possible other licenses for mobile connectivity and a full- or part-time administrator to turn dials and watch the blinking lights. That doesn't mean, however, that it's out of reach for small companies with small budgets. Exchange is, after all, the gold standard. If it can be had for the price of pennies on the dollar then organizations should look into getting it.

All of Exchange's features work over the Internet just like they would work on a company network. That means someone else can host the server and take care of all the licensing. This setup is known as hosted Exchange. Any individual or organization with limited resources can find online deals for hosted Exchange accounts starting at about $35.00 a month for three users.

Hosted solutions can be ideal because the services includes 24/7 technical support, spam filtering and often free client software such as Microsoft Outlook for Windows or Microsoft Entourage for Mac. Be sure that the service provider explicitly offers support for Macs. While most any hosted Exchange solution should work, having someone who can troubleshoot Mac connectivity or performance issues is worth finding. Mobile phone and Blackberry services are usually extra.

Kerio bills its MailServer product as a Microsoft Exchange alternative right under its name on the product website <http://www.kerio.com>. While MailServer may not be feature-for-feature identical to Exchange Server, it comes close to offering both the major and minor features that users familiar with Exchange want.

Kerio has made MailServer to offer a nearly identical end-user experience to that of Exchange Server and it offers its administrators a few features that Exchange Server doesn't have out of the box that would require extra licensing or would be better-suited for a third-party add-on. They include built-in mobile support, built-in spam filtering, built-in antivirus integration (with McAfee antivirus offered for an additional cost), built-in E-mail archiving and a built-in backup system.

Like Exchange, MailServer can be run on servers in-house or is available as a hosted solution from service providers on the Internet. Installation and setup are simple straightforward.

"ZCS" is another collaboration suite that is especially popular with Internet Service Providers. It too bills itself as a Microsoft Exchange alternative on its home page and even features a 45-minute "Zimbra vs. Exchange" webinar <http://www.zimbra.com/about/webinar_form.php?showID=10>.

What makes ZCS unique in this round-table of collaboration systems is that its server uses several open source projects that are well known and understood in the open source community. These include Postfix for mail, OpenLDAP for directory services, ClamAV for antivirus protection, SpamAssassin for message filtering and a few others. Unlike Exchange, and MailServer, the ZCS installer interface is presented through a command line interface, which may intimidate novice administrators.

Zimbra offers a free open-source version of its product, licensed under the "Yahoo! Public License (YPL)", as well as a commercial version that includes some non-open source pieces.

MailServer and ZCS are just examples of Exchange Server alternatives and should not be considered to be "the best" solutions available. Instead, they represent the idea that Exchange Server alternatives don't necessarily have to operate or behave just like Exchange to be viable options. For example, Mac OS X Server with its Mail server, iCal server and Open Directory, could be considered as an alternate messaging collaboration system. A search on the Internet for "Exchange Server alternatives" reveals several more products as well as plenty of side-by-side feature comparison articles.

This is where product differences come to light. Exchange Server alternatives may not reveal themselves as very different when they too can send mail, schedule events and sort contacts, but the engines behind the services can differ like the engines of two cars. One might offer fast performance whereas the other is all about the smooth ride.

With Exchange Server 2007, Microsoft introduced a new protocol called Exchange Web Services (EWS), which is the foreseeable future of Exchange. EWS is not like the years-old tried-and-true POP and IMAP protocols and it's certainly nothing like its proprietary predecessor MAPI. Anyone considering something other than Exchange needs to look at this protocol heavily!

Simply put, no other mail server uses EWS. It is Exchange-only. Is that good or is that bad?

Remember, unique features are what drive product differences and EWS is at the core of Exchange Server's offering. This new protocol is based on HTTP, XML and SOAP standards, so the fact that it's proprietary isn't necessarily a drawback. Not only is it extensible, it's very portable and this means it has a bright future going forward. One single protocol has the unique ability to deliver multiple kinds of information (mail, calendaring and contacts, for example) whereas Exchange alternatives must support three different protocols to deliver the same information.

Because EWS is delivered via HTTP, it has a good probability of surviving proxy servers and other Internet-filtering devices that block most everything but port 80. In corporate environments where VPN is required to access internal resources, EWS can be delivered externally without VPN and it can securely provide the same access to information as if sitting on the company network.

Compare this to MailServer, Zimbra Collaboration Suite and any other collaboration suites. Most everything else will use a combination of different protocols to accomplish the same delivery of information. IMAP will most likely sync mail, CalDAV will most likely provide calendaring services and some form of LDAP will most likely provide directory services. All three of these protocols have years of reliability and stability to their credit and they are based on RFC standards.

The new EWS protocol and the older RFC protocols ultimately accomplish the same thing. They move the data between the server and the user. The trade-off is, again, performance vs. a smooth ride.

Where will these collaboration services live and who will support them?

With Microsoft, the choice of operating system for running Exchange Server is made easy: Windows—or rather, Windows Server, which is more expensive and more complex to support than its desktop counterpart. Exchange Server 2007 requires a 64-bit platform and all the software and hardware that go with it. It may run on a 64-bit workstation-class machine but it certainly won't run on Windows XP and definitely won't run on Mac OS X Server or Linux without virtualization. Even then, it will require a Windows Server license.

Exchange Server alternatives shine here. Because they are based in older and well-established standards, they can take advantage of all the OS porting that has been done in the open source world.

Zimbra Collaboration Suite, for example, runs on Linux servers such as Red Hat, SUSE and Ubuntu and UNIX-based systems like Mac OS X. Kerio MailServer runs on similar systems and goes so far as to support Windows too. MailServer even expands its offerings to non-server operating systems. An old 1GHz Windows XP machine or PowerMac G4 with Tiger is a likely candidate for a small messaging collaboration server.

Figure 3. Candidate for a small messaging collaboration server

This means that for little investment in hardware and software, any organization can install a complete messaging system and support it on its own. However, that doesn't necessarily mean any organization should go into server support. A whiz-kid graphic artist might be able to maintain and troubleshoot a relatively simple setup, but should he really take help desk calls while doing page layout? When a company is big enough to need collaborative messaging but too small to hire an IT guru, then it needs to turn to hosted solutions.

Most every, if not every, collaborative messaging system is offered as a hosted service available via the Internet. Along with hosted Exchange are hosted MailServer and hosted ZCS services and a smattering of service levels that range from individual plans to small- and even medium-size organizations. Microsoft offers its own hosting service at http://www.microsoft.com/online/products.mspx.

Some services, such as Google Apps are offered only online, which makes many in-house IT folks uncomfortable. Messaging systems are often mission-critical and when they go down the last thing IT wants to tell its CEO is, "I've called and opened a ticket. They'll get back to us as soon as they can." Viable Exchange alternatives need to be able to offer in-house as well as out-sourced hosted solutions.

Administrators would like a simple and reliable solution to support, however, their job is just to keep the car running for the driver. The end-user experience is far more important. Ultimately, systems are put into place to support the needs of those connecting to them.

An Exchange solution or any of its alternatives shouldn't dictate which client applications are used.

For a long time, Microsoft ignored this model. Their proprietary mail protocol, MAPI, was complex, closed and undocumented, which prevented competitors from developing their own client solutions. The result was that in order to get full Exchange functionality, customers had to also license the only Exchange-compatible client, Outlook.

Along came Microsoft Entourage for Mac. The Macintosh Business Unit (MacBU) at Microsoft was tasked with taking its existing POP and IMAP client and turning it into an Exchange client as well. At this time, around 2003, WebDAV was growing popular and everyone was jumping on the bandwagon. Exchange Server's Outlook Web Access (OWA) was built on WebDAV and MacBU took advantage of it in the spirit of trying to keep Entourage built on Internet standards rather than proprietary standards.

Literally, if MacBU could develop a mail client using open standards then so could anyone else and that's what Apple did with Mail 2.0. While it still used IMAP for mail, it did take advantage of WebDAV for calendaring as well as LDAP for directory services and for the first time on a Mac, three non-Microsoft client applications came together to offer basic Exchange-like functionality.

Fast forward three years and Exchange Web Services debuts in Exchange Server 2007. EWS is the result of collaboration between the Exchange Server development team and MacBU to develop an openly documented standard that anyone can utilize. Again, Apple took the lead as the first non-Microsoft company to develop against the new protocol and Mail 4.0 nearly debuted as the first Mac client for EWS. (The folks at MacBU released their Entourage for EWS client just weeks before Mac OS X 10.6 was released.)

The moral of this story is that had Microsoft continued down the path of proprietary and closed systems, it would not have become the gold standard supporting clients on different platforms. Yes, it would probably still have a huge foothold in the corporate Windows world, but someone like Kerio or Zimbra would have been dominating the Mac market. Exchange alternatives should follow this example and open their doors to client applications other than their own.

Feature rich clients aren't always accessible or even practical. Exchange Server offers Outlook Web Access (OWA) for account access through a standard web browser as well as ActiveSync for account access on mobile devices.

OWA has made Exchange users on Macs feel like second-class citizens for more than a dozen years. That's because the Exchange Server developers wanted to provide a rich experience through a web browser to their clients. However, they once again used a proprietary Microsoft technology. This technology was ActiveX and although it wasn't limited to just the Windows operating system, no other platforms really adopted it. ActiveX became ipso facto a Windows-only technology. This left all browsers that weren't Internet Explorer for Windows with the OWA "Lite" version and it paled in comparison to what the full version could do.

Figure 4. Webmail views from Exchange Server, MailServer and ZCS

Both Kerio and Zimbra have clearly seen this as an opportunity to shine. MailServer and ZCS offer webmail support, as do most modern mail servers. Instead of using ActiveX, however, to offer their rich experience, they employ Ajax, which is built on JavaScript and XML. Again, these are two open and standards-based technologies that anyone can utilize. All popular modern web browsers for both Mac and Windows support Ajax and even Linux browsers can be full webmail citizens.

Most any user connecting to his MailServer or ZCS account can have the experience of dragging and dropping messages into mail folders or right-clicking items and selecting commands from a contextual menu. Columns are resizable and customizable and instead of creating a new browser window, Command-N creates a new mail message window.

Of note, Exchange Server 2010 will also adopt an Ajax solution or something similar that will allow all web browsers to receive the same feature-rich experience that only Internet Explorer for Windows users enjoy today. Its availability for public consumption has been announced by Microsoft as "second half of 2009", but it was released to manufacturing (RTM) in September, which means it should be available around October or November of 2009. Companies that are early adopters of technology and consumers with hosted Exchange Server accounts will likely be the first to kick the tires and take it for a spin.

The new office is in the pocket or purse. Mobile phones empower people (or enslave them, depending on the point of view) by keeping them tied to their collaborations server 24/7/365. With the popularity of Windows Mobile, Blackberry and the iPhone, the need to be connected all the time has skyrocketed.

However, the technology to keep connected isn't as clean-cut as deciding which protocol works best. Again, Microsoft's influence has the upper hand.

"Push" is the term marketers like to use when describing the mail feature on phones. It has come to mean, "My mail comes to me; I don't have to check it." What's really happening is one of three things. The phone is periodically checking accounts for updates automatically (usually about every 15 minutes), the phone is connecting to an ActiveSync-enabled account that keeps a long HTTP session open and periodically renews it (again, about every 15 minutes) or the phone is a Blackberry and is using a Blackberry mail server to send and receive content.

Standard mail accounts (POP and IMAP) rely on the first method where the phone polls for mail automatically. The downside to this type of connection is that the less frequently that the phone checks for mail, the less the messages are received in real time. The more frequently the phone checks for mail, the greater the battery drain and the less ability to be truly mobile.

Figure 5. IMAP accounts will poll about every 15 minutes for new mail

Exchange-type accounts use a Microsoft proprietary protocol call ActiveSync. It works over HTTP by establishing a connection over the Internet to the Exchange Server and then keeping that connection open. Typically, when two devices communicate over a network, they transmit data and then close the session. ActiveSync works by waiting up to about 15 minutes before closing a session and this allows the server to pass a message back to the phone as soon as it is received. If the server doesn't have anything to send within that time period, it closes the session with the mobile device, which then immediately opens a new 15-minute session. The advantage of ActiveSync is less battery drain and messages are received in real time. The downside is that Microsoft owns the protocol and anyone wishing to use it must license it.

Figure 6. ActiveSync is an immediate two-way sync

Blackberry devices rely on a Blackberry server to be connected to the Exchange Server and then act as an intermediary to forward information back and forth. It too uses HTTP to handle much of its communications and therefore has a lower drain on the battery. The advantage of a Blackberry server is that it can handle more types of information, such as documents, and it can connect to other collaboration systems like Domino and GroupWise. The downside is that this is another proprietary solution that must be licensed and only works with Blackberry devices.

How have the Exchange alternatives decided to handle mobile connectivity? Kerio has licensed ActiveSync from Microsoft, which opens the doors for all Windows Mobile, iPhone and even Blackberry devices running ActiveSync for Blackberry. They will also help integrate a Blackberry system with MailServer for an additional fee. Zimbra has opted to license ActiveSync only for ZCS Network Edition (their commercial product). Remember, Zimbra offers an open source version of their collaboration suite too, but it will have fewer features. Mac OS X Server mobile clients will need to rely on periodic polling to receive their messages.

If mobility is crucial to a company's collaboration system then either an ActiveSync or a Blackberry server solution is required. While IMAP and CalDAV are the common denominators for most every collaboration system on the market, these two protocols have no built-in mechanism for "staying alive". A semi-manual check by the device itself or a protocol made for low-impact syncing will be required.

Like any other product, money invested is directly proportional to the features enjoyed, or to put it simply, "You get what you pay for!" Don't take that to mean that Exchange Server is the answer for everyone and that settling for anything else is really just settling for less. Exchange Server obviously isn't for everyone or else everyone would have it and no one would be offering alternative solutions.

Exchange Server is expensive to own and maintain compared to other solutions (after all, it is the gold standard) but its benefits aren't 100% unique. Many of its features are matched by taking advantage of its open technologies, such as EWS, or by licensing its closed technologies, such as ActiveSync. Where an alternative collaboration server solution may not be able to match some of its features, many mimic them by substituting IMAP with scheduled polling for true "push" or by substituting CalDAV calendaring for Exchange calendaring. Depending on the needs of the end-user, one may be just as good as the other.

When owning is not an option then leasing may be the solution. Allowing someone else to assume the licensing, maintenance and support costs for a monthly fee is a great way to "try before you buy" as well as a great way to stay financially flexible in a fluctuating economy. On the other hand, bringing in a low-cost solution and supporting it in-house on inexpensive hardware is appealing to those who need the control over crucial systems.

Most importantly, the end-user should have control over his experience as much as possible. Forcing him to use a certain mail client or mobile device because "that's what the server supports" is like telling him he has to use Windows because "that's what IT supports". The tail shouldn't wag the dog.

In the end, all the end-user knows is that he needs to access his mail, calendar and contacts so that he can effectively collaborate with his co-workers in real time from anywhere using any method available. Chances are that he has no idea what "Exchange" is and doesn't really care what system he is using.

William Smith is a technical analyst supporting Macs in a Windows world in the Twin Cities, a six-year Microsoft MVP and is co-founder of the Entourage Help Blog http://blog.entourage.mvps.org. He can be reached at bill@talkingmoose.net.