Microsoft Exchange Server 2003 review

ES2K3 inherits new capabilities and features from Windows Server 2003 (WS2K3) too, of course, so for a proper understanding of the full ES2K3 product you have to be running on WS2K3 as well. This isn't an onerous requirement, providing you remember the matrix of what runs on what. You can run any ES2K/2K3 on any Windows 2000/2003 combination with one exception - you can't run ES2K on W2K3. So the upgrade route is clear: start with ES2K on W2K, move to ES2K3 on W2K, and then move to ES2K3 on WS2K3.

Since you inherit the underlying capabilities of WS2K3, the clustering support is much better in ES2K3 compared to previous versions in that you can have up to eight machines in a cluster. However, the underlying limitations of mailboxes per store and so forth are still in place, so an Active/Active cluster solution has its limitations. But you can build better and more resilient solutions than before. ES2K3 also benefits from the snapshot file system capabilities of WS2K3. So if you're using a SAN (Storage Area Network), for example, you can break the mirror on the SAN and back up one half in real-time while the other part keeps running. Support for SAN and NAS (Network Attached Storage) is much better in WS2K3/ES2K3 than in previous versions, so you should be looking to these versions if you want to deploy a large SAN.

If you have a large multiserver implementation of Exchange Server, you'll know all about front-end/back-end server deployments, where you split the capabilities of Exchange Server into two halves and run them on different servers. In this environment, a good change is the removal of the requirement for Enterprise Server versions of ES2K3 as front-end servers to back-end Enterprise Server ES2K3s, which will be a significant licensing cost reduction for large sites.

Now let's look at the more user-oriented features that ES2K3 brings to the table. At this point, we need to assume you have Outlook 2003 installed as well, because the new online/offline capabilities of that pair are only available when you run both pieces. In a nutshell, you can run Outlook in a local cache mode whereby it keeps the data locally to the machine, yet pulls and pushes through the back-end ES2K3 server too. Connecting through port 80 is another feature of this combination and means you can actively synchronise over the Internet without needing to resort to Virtual Private Networks or the equivalent.

OWA (Outlook Web Access) has always been a killer feature of Exchange Server - being able to read your mail, contacts and calendaring from anywhere just by using a browser is a powerful capability. With ES2K3, it has been dramatically improved. If you have a good enough browser, such as Internet Explorer 6, you get a rich desktop client running in the web browser that's almost feature-for-feature compatible with the full native Outlook client. You can right-click on things, drag and drop them and do all that sort of rich interaction. This is an astonishing and amazing piece of web-development work and sets the benchmark for such programming. If you work on a lesser browser, the experience is obviously scaled back a little, but it's still light years ahead of the capabilities in previous versions of ES.

As a child of OWA, OMA (Outlook Mobile Access) is a new feature. OMA is a super-lightweight version of OWA aimed at the simple web browsers found in PDAs and phones. You get full access to your inbox, including contacts and so forth, and it does so in a lightweight data way that doesn't chew up lots of bandwidth, unlike OWA which is traffic heavy. If you have a Pocket PC 2003 device or one of the forthcoming 2003 Windows Smartphones, you can even do a full ActiveSync synchronisation in real-time while away from the office. This is a significant step forward and has been enabled by building in technology that was previously available in the Mobile Information Server add-on to ES2K.