Microsoft Exchange has come a long way since Exchange 4.0 was released in 1996.  Today, Exchange 2010 connects not only Microsoft Outlook client on the LAN and over the Internet, but supports POP, IMAP, Outlook Web Access (OWA) and Exchange ActiveSync for mobile and tablet devices.

As you can imagine, administrators are finding themselves having to grapple with issues such as high-availability setups in load-balanced deployments, but servicing the various quirks (or bugs) that are faced by users accessing Exchange services via any of the above vectors.  While it would be next to impossible to cover every version and deployment of Exchange, I want to go through a number of tips that I hope will help you save some time when troubleshooting Exchange ActiveSync.

First determine version of Exchange ActiveSync on the client device

One of the basic steps when attempting to solve a client-server issue involves first establishing the type of system or software running on the other end; this much is true when troubleshooting Exchange ActiveSync.  On this front however, it is important to not only determine the model of the device, but it is also crucial not to make assumptions without first determining the exact operating system (OS) revision.

This is because OSs can and do get upgraded, with a new version either implementing things differently or supporting more features than the previous iteration.  A prime example would be the iPhone 3GS, which implements varying support for Exchange ActiveSync depending on which version of iOS is installed.

Of course, you will also need to determine the version of Exchange ActiveSync supported by your server.  Fortunately, this can be determined relatively easily: From the oldest to the newest, Exchange 2003 SP2, 2007, 2007 SP1, 2010, 2010 SP1 supports Exchange ActiveSync 2.5, 12.0, 12.1, 14.0 and 14.1 respectively.

Check for device-side issues

Fellow blogger John P Mello Jr beat me to this one when he wrote New iPhone OS not playing nice with Exchange.  Email and system administrators with any time under their belt will know all about client devices spoiling the party by not working as they were supposed to.  Ditto to Apple’s iOS 4.2, which apparently “doesn’t play nicely with Microsoft Exchange 2003″ observed John – resulting in calendar events that disappears.  I did a quick check with a friend who manages a large number of Exchange Servers for a living, and it would appear that the carnage this time round is considered minor, and “did not result in any Exchange-related harm.”

This was not the case with the original iOS 4 update, which resulted in significant artificial load being placed on Exchange Servers.  My point here is that many of the problems with Exchange ActiveSync originate from client devices and not Exchange Server.  As such, administrators would be remiss in not exploring the possibility more thoroughly.

Read up on resources on ActiveSync

Resources pertaining to Exchange ActiveSync are not exactly bountiful, unfortunately.  I did a quick search and also asked around, but there appear to be no books written about this topic.  So far, anything substantial about this topic can be found on either TechNet or MSDN.

For starters, a primer that you might want to consider reading first would be an earlier post on TheEmailAdmin where I wrote about Understanding the Different Implementations of Exchange ActiveSync.  In addition, administrators curious about the differences between how BlackBerry “push” email differs from Exchange ActiveSync will want to read Which uses less traffic: BlackBerry Push or Microsoft Direct Push?

Reliability of wireless mobile networks

Devices that support Exchange ActiveSync are typically smartphones or tablet devices such as the iPhone, iPad or the increasing number of Android-based tablets such as the Dell Streak or Samsung Galaxy Tab.  As should be quickly evident, the common denominator among these devices is how they rely mostly on wireless mobile networks for data connectivity.

As an administrator, it is important to realize that mobile networks can be less reliable and prone to its share of quirks compared to Wi-Fi or wired networks.  When troubleshooting, administrators need to factor in the higher latency of mobile networks, as well as poor coverage as sources of potential problems.  Microsoft’s decision to base the protocol on HTTP and XML, while making it easy to forward across firewalls and proxy servers, means that Exchange ActiveSync has a relatively high protocol overhead.  From personal experience, I can attest to the fact that it fares poorly in areas with less than optimal wireless reception.

I have a few more pointers on troubleshooting Exchange ActiveSync which I shall cover next week, so stay tuned!

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