Seven ways to push mail to the iPhone -- without Exchange

Computerworld - In Part 2 of my series on rolling out the iPhone as a business device, I talked about integration in an Exchange environment. Though the iPhone supports all common e-mail protocols, Exchange is the only business-oriented option for offering push notification of new messages as well as over-the-air updates to calendar and contact items. Sure, push notification and update is supported by Apple's MobileMe -- and push e-mail notification is supported for Yahoo Mail accounts. But neither of these would be considered viable options for most businesses.

Exchange may be the most common e-mail and collaborative tools package on the market, making it a logical choice for Apple to choose for enterprise support. Despite its widespread use and potentially broad feature set, Exchange isn't always the optimal choice for every organization, however. Exchange licensing can become prohibitively expensive, particularly for small organizations, and successfully deploying and managing Exchange can be a challenge, given the broad array of features and options it offers. Its very tight integration with Active Directory, a plus in many situations, can also be a downside for environments based on other platforms such as Novell, Unix and -- ironically -- Mac OS X Server and Apple's own Open Directory..

That can be a problem for companies that are looking to roll out the iPhone but are unwilling or unable to rely on Exchange as well. The generally accepted option is to use POP/IMAP e-mail accounts on the iPhone and rely on iTunes to sync contact and calendar data -- from Outlook on Windows, or Address Book and iCal on the Mac -- to the iPhone. Though that will work, it eliminates the option of receiving instant notification of e-mails, and calendar and contact updates. It also prevents iPhone user access to a shared central contacts database, such as Exchange's Global Address List, through the Contacts app.

But there are other options. Although the iPhone's documentation names Exchange specifically, Apple actually licensed and implemented Microsoft's ActiveSync protocol, which was developed for Exchange. Apple is not alone. In fact, several other mail and groupware server products, both commercial and open source, are available that implement ActiveSync and allow mobile clients -- including the iPhone and desktop applications such as Outlook -- to access the same push and over-the-air features available from Exchange.

Here's a rundown of those alternatives:

Kerio MailServer

Kerio MailServer is a commercial groupware product that offers features similar to Exchange's, including mail, centralized contacts, calendar, notes, tasks and public folders. One of its big advantages is that, in addition to ActiveSync and native access from both Outlook and ActiveSync mobile devices, Kerio fully supports access through other client protocols without the need for add-on components -- although not all features are available to all client products. Using a sophisticated Web interface, Kerio allows LDAP access to its central contacts database by any contact or e-mail app that supports LDAP lookup, as well as calendar access from any CalDAV client, including Apple's iCal.