At its core, Microsoft Exchange Server 2007 is an email, calendaring, and address book system that runs on a centralized Windows Server 2003 server system. However with the release of Exchange 2007, now the sixth major release of Exchange in the 12-year history of the product, Microsoft has made significant improvements in the areas of security, reliability, scalability, mobility, and unified communications. For those Exchange experts who are already very familiar with the product, you might choose to skip this section, jump to the “Exchange Server 2007 Versions and Licensing” section (because Microsoft has a slightly different way of licensing Exchange 2007), and then jump to the “What’s New in Exchange Server 2007” section to discover the latest and greatest in Exchange

So back to the basics of Exchange, with a centralized Exchange server holding mail messages, calendar appointments, contacts, and other user information, the Exchange environment provides a server-based storage of information. Users throughout the organization connect to the Exchange server from Microsoft Outlook, from a web browser, or from a variety of other client systems to get access to their email and other information.

For larger organizations, multiple Exchange servers can be added to the environment hosting mailbox information of the users. Microsoft has split the roles of servers in an Exchange environment, where some servers are dedicated for antivirus and antispam filtering, and other servers are dedicated to routing messages throughout the organization. The “Understanding Exchange Server 2007 Server Roles and Mail Flow” section discusses these roles in more detail.

Understanding the Evolution of Exchange

For those new to Microsoft Exchange, this section covers the history of the Exchange product line. Sometimes as a newcomer to a technology, it’s hard to jump right into the technology because everyone working with the technology refers to previous versions without taking into consideration that some people might not remember what was in the last revision, or in the product a couple of revisions back. So, this section is intended to give you a little history of Exchange so that the version numbers and major notable features and functions make sense.

Exchange Server 4.0

The first version of Microsoft Exchange, despite the 4.0 designation, was Exchange Server 4.0. Some people ask, “What happened to Exchange Server 1.0, 2.0, and 3.0?” For a bit of trivia, prior to Exchange Server 4.0, Microsoft had MS-Mail 3.0 (and MS-Mail 2.0); prior to that, it was a product called Network Courier Mail that Microsoft bought in the early 1990s.

Microsoft Exchange 4.0 had nothing in common with MS-Mail 3.0; they were completely different products and different technologies. The first rollouts of Exchange 4.0 back in 1996 were on Windows NT Server 3.51, which anyone with old NT 3.x experience knows that it was a challenging operating system to keep fully operational. “Blue screens” in which the operating system would just lock up were common. Anything that caused a system error usually resulted in a blue screen, which meant that every patch, update, service pack addition, installation of antivirus software, and so on frequently caused complete server failures.

However, Exchange 4.0 was a major breakthrough, and organizations started to migrate from MS-Mail to Exchange Server 4.0. One of the biggest reasons organizations were migrating to Exchange 4.0 was that in 1996, the Internet was just opening up to the public. The specifications for the World Wide Web had just been released. Organizations were connecting systems to the Internet, and one of the first real applications that took advantage of the Internet was Microsoft Exchange 4.0. Organizations were able to connect their Exchange 4.0 server to the Internet and easily and simply send and receive emails to anyone else with an Internet-connected email system. MS-Mail 3.0 at the time had a Simple Mail Transfer Protocol (SMTP) gateway; however, it worked more on a scheduled dial-up basis, whereas Exchange 4.0 had a persistent connection to, typically, Integrated Services Digital Network (ISDN) or 56-KB frame connections to the Internet. And with Windows NT 4.0 shipping and being a much more solid infrastructure to work from, Exchange Server 4.0 was much more reliable than MS-Mail was for centralized organizationwide email communications.

Exchange Server 5.0

Exchange Server 5.0 came out in 1997 and was built to run on Windows NT 4.0, which proved to add more reliability to the Exchange Server product. In addition, Exchange 5.0 supported the first version of Outlook that to this day has a similar mailbox folder concept with the Inbox, Sent Items, Calendar, Contacts, and other common folders duplicated by mail systems throughout the industry. With the support for the Microsoft Outlook (97) client, Exchange also included calendaring directly within the Exchange product. In Exchange 5.0, the calendaring product was Schedule+, which was an add-on to Exchange 4.0, meaning that a user’s email and calendaring weren’t tied together, so Exchange 5.0 tied email, calendaring, and address books all together. With a service pack to Exchange 5.0, Microsoft also released the first version of Outlook Web Access (OWA) so that those who accessed the new World Wide Web could get remote access to their email on Exchange. Back in 1997, this was a big thing as web mail was a new concept, and Exchange 5.0 had web mail built in to the messaging product.

Exchange 5.0 also had better third-party support for things such as fax gateways, unified voice mail add-in products, and document-sharing tools, leveraging shared public folders in Exchange. With better reliability, third-party product support, and a growing base of customers now migrating from MS-Mail and cc:Mail to Exchange, the Microsoft Exchange marketshare started to skyrocket.

Exchange Server 5.5

In 1998, Microsoft released Exchange 5.5, which some organizations are still running in their networking environment. With Exchange 5.5, Microsoft worked out the bugs and quirks of their first two revisions of the Exchange product, and significantly better integration occurred between email, calendar, contacts, and tasks than in previous releases of Exchange. Microsoft also expanded the support for a larger Exchange database used to store messages, so instead of being limited to 16GB of mail with earlier releases of Exchange, organizations could upgrade to the Enterprise Edition of Exchange 5.5 that provided more than 16GB of data storage. With larger storage capabilities, Exchange 5.5 greatly supported large corporate, government, and organizational messaging environments.

Along with Exchange 5.5, OWA was improved to provide a faster and easier-to-use web client. The concept of site connectors was expanded with Exchange 5.5 to provide a larger enterprise Exchange environment with distribution of administration, message routing, and multilanguage support. Most organizations that hadn’t migrated off of Exchange 5.5 earlier had made their migration to Exchange 2000 and 2003. Exchange 5.5 for the most part is now out of environments or will soon be migrated to Exchange 2003 in anticipation of the organization ultimately migrating to Exchange 2007.

Exchange 2000 Server

Exchange 2000 Server came out in 2000 right after the release of Windows 2000 Server and the first version of Microsoft Active Directory. The biggest change in Exchange 2000 is that it used Active Directory for the Global Address List (GAL), instead of Windows NT having its list of network logon users and Exchange 5.5 having its own directory of email users. Active Directory combined a network and email user account into one single account, making the administration and management of Exchange much simpler. Exchange 2000 also went to an ActiveX version of the OWA client instead of a straight Hypertext Markup Language (HTML) version of the web access, thus providing users with drag-and-drop capabilities, pull-down bars, and other functionality that made the web access function much easier for remote users.

Exchange 2000, which is required to run on top of Windows 2000, became much more reliable than Exchange 5.5, which ran on top of Windows NT 4.0. However, because Exchange 5.5 can run on top of Windows 2000, many organizations made the shift to Exchange 5.5 on top of Windows 2000. These organizations also gained better performance and reliability, which is why many organizations did not migrate from Exchange 5.5. However, Windows 2000 provided Exchange 2000 a stable operating system platform from the beginning. Also by 2000, Novell’s popularity was dramatically decreasing and organizations were migrating from Novell GroupWise to Exchange 2000, so the Microsoft marketshare continued to grow.

Exchange Server 2003

Exchange 2003 was the most recent major product release prior to the current Exchange 2007 product line. Exchange 2003 added mobility for users to synchronize their Pocket PC mobile devices to Exchange. In addition, OWA got yet another major face-lift mirroring the OWA interface with the normal Microsoft Office Outlook desktop client. With better remote support, Exchange 2003 became more than an office-based messaging system—it also greatly enhanced an organization’s ability to provide remote and mobile users with email anytime and anywhere.

Exchange 2003, running on top of Windows Server 2003, took advantage of additional operating system enhancements, making Exchange 2003 an even more reliable and manageable messaging system. Windows 2003 clustering finally worked so that organizations that put Exchange 2003 on top of Windows 2003 were able to do active-active and active-passive clustering. In addition, clustering went from two-node clusters to four-node clusters, providing even more redundancy and recoverability.

Exchange 2003 also introduced the concept of a recovery storage group (RSG) that allowed an organization to mount an Exchange database for test and recovery purposes. Prior to Exchange 2003, an Exchange database could only be mounted on an Exchange server, typically with the exact same server name and for the sole purpose of making the database accessible to users. The recovery storage group in Exchange 2003 allowed an Exchange database from another Exchange server to be mounted in an offline manner so that the Exchange administrator can extract corrupt or lost messages, or possibly even have the database in a “ready mode” to allow for faster recovery of a failed Exchange server.

Exchange Server 2003 Service Pack 2

Although not a major release of Exchange, it is significant to note the late major service pack for Exchange 2003, which is Exchange 2003 Service Pack 2. Exchange Service Pack 1 introduced cyclic redundancy check (CRC) error checking of the Exchange database. For 10 years, information written to Exchange was done without error checking, so prior to 2005, Microsoft Exchange had a bad reputation for having corruption in its databases any time the databases got too large. With the release of Exchange 2003 SP1, error checking brought Exchange to a whole new world in better reliability.

Exchange 2003 SP2 added to the reliability and security of Exchange by introducing support for SenderID message integrity checks as well as enhanced journaling of messages that captured a copy of messages in Exchange and locked the original copies of the messages in a tamperproof database that allowed for better support for regulatory compliance auditing and message integrity.

Exchange 2003 SP2 also added in direct push for mobile devices so that instead of having a Windows Mobile or Pocket PC device constantly “pull” messages down from Exchange, Exchange 2003 SP2 pushes messages to mobile devices, thus preventing constant polling by the mobile device, which increases battery life and enables Exchange and mobile devices to remain synchronized in real time.

Exchange Server 2007 Versions and Licensing

One major change to Exchange 2007 is that it only comes in an x64-bit version that requires Windows 2003 x64-bit to run as the core operating system. Although Exchange 2007 requires Windows 2003 x64-bit to run the Exchange server software, an organization can still run 32-bit Windows 2003 domain controllers, global catalog servers, and even Windows NT 4.0 and Windows 2000 member servers throughout the environment. Just the Exchange 2007 servers need to run x64-bit.

This means that organizations need to make sure their server hardware is x64-bit. Prior to the release of Exchange 2007, most organizations were buying x64-bit hardware anyway because many hardware vendors stopped shipping 32-bit hardware as much as a year to 18 months prior to the release of Exchange 2007. The benefit of x64-bit hardware is that you can still run 32-bit Windows and 32-bit software on the hardware until such time that you want to just reinstall 64-bit Windows and 64-bit software on the systems.

Organizations with volume licensing agreements with Microsoft do not need to purchase or upgrade their Windows licenses from 32-bit to 64-bit. A Windows 2003 server license is a Windows 2003 server license, so regardless of whether the system is 32-bit or 64-bit, the organization’s server licenses remain the same.

Choosing the Standard Edition of Exchange 2007

As with previous versions of Exchange, Microsoft has two different versions, a Standard Edition and an Enterprise Edition of the software. The Exchange Server 2007, Standard

Edition is the basic message server version of the software. The Standard Edition supports five data stores. The Standard Edition has full support for web access, mobile access, and server recovery functionality.

The Standard Edition is a good version of Exchange to support a messaging system for a small organization, or as a dedicated Edge Transport, Hub Transport, or Client Access server for a larger environment. Many small and medium-sized organizations find the capabilities of the Standard Edition sufficient for most messaging server services, and even large organizations use the Standard Edition for message routing servers or as the primary server in a remote office. The Standard Edition meets the needs of effectively any environment wherein a server with a limited database storage capacity is sufficient.

Expanding into the Exchange Server 2007 Enterprise Edition

The Exchange Server 2007, Enterprise Edition is focused at server systems that require more Exchange messaging databases and support for clustering for higher availability. With support for up to 50 databases per server, the Enterprise Edition of Exchange 2007 is the appropriate version of messaging system for organizations that have a lot of mailboxes or a lot of mail storage. The Enterprise Edition is also appropriate for an organization that wants to set up clustering for higher reliability and redundancy of the Exchange environment.

Exchange Enterprise CAL Versus Standard CAL

The basic differences of the Exchange Enterprise versus Standard server editions is the differing number of databases supported and higher availability clustering support. Beyond these basic differences, Exchange 2007 introduces an Enterprise client access license (CAL) and a Standard CAL. Either CAL can be used against either server edition and has no association between the server versions. Rather, the Enterprise CAL adds functionality such as providing the user a license for unified messaging (voice mail in Exchange 2007), per user journaling for archiving and compliance support, and the ability to use Exchange hosted services for message filtering (known as FrontBridge), or providing enhanced antispam and antivirus functionality using ForeFront Security for Exchange.

Organizations that had software assurance for Exchange will get upgraded to the Standard Exchange 2007 CAL, and those that want to add on unified messaging as well as the new journaling, antivirus, and antispam technologies can upgrade their licenses to the Enterprise CAL license.