The newest upgrade to Exchange 2003, based on our testing of the Release to Manufacturing version, is a welcome one, offering performance, security and anti-spam features that many users have longed for. The new Exchange Server 2003 includes an impressive list of features and enhancements and while this version might not boast enough new features to lure non-Exchange users to switch, the veteran Exchange shop will truly enjoy the enhancements.
Exchange requires Microsoft Windows Server 2000 Service Pack 3 or Windows Server 2003 software. Win Server 2003 provides some additional functionality to Exchange, such as support for an eight-node cluster. Also, the Volume Shadow Copy services, new in Win Server 2003, can provide database replication for the Exchange message stores. This copy of the database can be used for immediate failover, or can greatly widen your back-up window (if your back-up software also supports Shadow Copy).
Win Server 2003 is different than previous versions, with most of the services disabled by default. To ensure a successful Exchange 2003 installation, new deployment tools are included to help users configure Windows Server and Active Directory correctly, and then deploy Exchange 2003. The tools function like checklists to ensure that you've followed the necessary steps. For example, the deployment tools not only explain to first configure Active Directory, but also show how to check the configuration. It will not let you proceed until you've checked off each task in the list. Installing or upgrading, all at once or in pieces, the deployment manager can explain how to proceed.
A welcomed new feature in Exchange 2003 is the ability to combat unwanted e-mail and spam (Microsoft calls it 'junk e-mail.'). Exchange now has some additional filtering available at the Simple Mail Transfer Protocol gateway, the entry point where the outside world delivers e-mail to you. Messages can be blocked based on the user or domain where the mail claims to be from, or based on who the message is intended for. Delivery connection attempts can be denied based on the origination address. Several anti-spam features are also included on the new Outlook client.
Another tool that many will appreciate is the Mailbox Recovery Center. In the past, if the Active Directory account became disassociated from the user's mailbox (through corruption, deletion and the like), the only solution was to create a new, empty mailbox for that user. The Mailbox Recovery Center now gives administrators the ability to discover "orphaned" mailboxes and re-link them with Active Directory accounts. It also will warn of conflicts, for example if one mailbox is assigned to two users.
Distribution lists also received some attention in this release. First, the caching process was redesigned so membership and other queries against a distribution list are completed much faster. We didn't benchmark against an older Exchange system, but Microsoft says that on average, 60% fewer Active Directory queries are made in Exchange 2003. Instead of making a new query to Active Directory, the results are more frequently available in cache. Second, a new type of distribution list was created, the Query-Based Distribution Group. A query can be used to select users or other groups based on many of the fields in the Active Directory. For example, you now can find everyone in sales or everyone with the title of "manager." This query is executed each time it is invoked, so it is always current.
Another performance enhancement is better virtual memory usage. Exchange now makes variable memory requests, based on the size of the system, instead of using "hard coded" values. Older versions would allocate many small blocks of memory to perform a task. Exchange 2003 now optimizes these requests into fewer, larger requests in order to not waste portions of memory. If Exchange discovers that it is not configured optimally, it sends a note to the Event Viewer to provide an idea of what changes to make.