Exchange Server 2003

Exchange Server 2003 debuted on September 28, 2003 Exchange 2003 (currently at Service Pack 2), or version 6.5, can be run on Windows 2000 Server (only if Service Pack 4 is first installed) and 32-bit Windows Server 2003, although some new features only work with the latter. Like Windows Server 2003, Exchange 2003 has many compatibility modes to allow users to slowly migrate to the new system. This is useful in large companies with distributed Exchange environments who cannot afford the downtime and expense that comes with a complete migration.

One of the new features in Exchange 2003 is enhanced disaster recovery, which allows administrators to bring the server online quicker. This is done by allowing the server to send and receive mail while the message stores are being recovered from backup. Some features previously available in the Microsoft Mobile Information Server 2001/2002 products have been added to the core Exchange product, like Outlook Mobile Access and server-side ActiveSync, while the Mobile Information Server product itself has been dropped. Better anti-virus and anti-spam protection have also been added, both by providing built-in APIs that facilitate filtering software and built-in support for the basic methods of originating IP address, SPF ("Sender ID"), and DNSBL filtering which were standard on other open source and *nix-based mail servers. Also new is the ability to drop inbound e-mail before being fully processed, thus preventing delays in the message routing system. There are also improved message and mailbox management tools, which allow administrators to execute common chores more quickly. Others, such as Instant Messaging and Exchange Conferencing Server have been extracted completely in order to form separate products. Microsoft now appears to be positioning a combination of Microsoft Office, Microsoft Office Live Communications Server, Live Meeting and Sharepoint as its collaboration software of choice. Exchange is now to be simply email and calendaring.

Exchange 2003 is available in three versions, Standard Edition and Enterprise Edition. Standard Edition supports one message database per server, and supports databases up to 16 GB in size. Beginning with the release of Service Pack 2, Standard Edition allows a maximum database size of 75 GB, but only supports 18 GB by default; a change is necessary to make the database size either larger or smaller than the new default 18GB size. Enterprise Edition allows a 16 TB maximum database size, and supports up to 4 storage groups with 5 databases per storage group for a total of 20 databases per server.

Exchange 2003 is included with both Microsoft Small Business Server 2003 Standard and Premium editions and is 32-bit only, and will not install on the various 64-bit versions of Windows Server 2003.

Microsoft Exchange Server uses a proprietary RPC protocol, of which only the API is documented (see MAPI). It was designed to be used by the Microsoft Outlook client. Email hosted on an Exchange server can be accessed using POP3 and IMAP4, with clients such as Mozilla Thunderbird and Lotus Notes. Both Microsoft Outlook and Novell Evolution are clients capable of using the advanced features of Exchange Server; Microsoft Entourage for Mac also has most of the advanced features implemented in the latest version. Exchange accounts can also be accessed through a web browser, known as Outlook Web Access (OWA). Exchange 2003 also features a WAP version of OWA, called Outlook Mobile Access (OMA).

Coupled with Windows Mobile 5.0 AKU2 or higher, Exchange Server 2003 SP2 supports "pushing" email to mobile devices - similar to the operation of BlackBerry devices

Unlike Exchange Server 2000, Exchange Server 2003 no longer ships instant messaging for internal corporate systems. Microsoft released Live Communication Server to provide those services as a standalone program.

Exchange 2003 Anti-Spam Filtering: Exchange 2003 added several basic filtering methods to Exchange. They are not sophisticated enough to eliminate spam, but they can protect against DoS and mailbox flooding attacks. Exchange 2000 supported the ability to block a sender's address, or e-mail domain by adding '*@domain.com', which is still supported in the 2003 server. Added filtering methods in Exchange 2003 are:

Connection filtering - messages are blocked from DNS RBL lists or from manually specified IP address/range
Recipient filtering - messages blocked when sent to manually specified recipients on the server (for intranet-only addresses) or to any recipients not on the server (stopping spammers from guessing addresses)
Sender ID filtering - Sender ID, a form of SPF
Intelligent Message Filter - A free Microsoft add-on that uses heuristic message analysis to block messages or direct them to the "Junk E-Mail" folder in Microsoft Outlook clients.