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Scaling New Enterprise Heights I ran Exchange 5.5 Release Candidate 1 in Network Computing's central Florida corporate test lab on a Compaq Computer Corp. ProLiant 5000 running NT 4.0. I upgraded to Service Pack 3 and Internet Information Server 3.0, which Exchange 5.5 requires for using Active Server components. I noticed immediately that things were different. Inserting the installation CD-ROM launched the Microsoft Internet Explorer browser, which let me select from server setup, release notes, online resources and documentation. These capabilities reflect Microsoft's shift toward browser-like technology within Exchange, the Outlook and Outlook Express clients, and even the OS itself.

Scalability suffered in prior releases of Exchange. The server was hobbled by a 16-GB limit on all stores (information, message and directory). In 5.5, the virtually unlimited stores are restrained only by server hardware, eliminating Exchange Server's inability to operationally handle more than 250 users per server, and reducing the number of servers needed, the number of server links to manage and the support costs.

Exchange also has added clustering support for single node failover in the event of a software or hardware failure.

Connectivity Capers There is nothing like being well-connected, and Exchange 5.5 goes the distance by offering IMAP4, LDAP 3 and several new connectors. It provides two options that make message retrieval faster for IMAP4 clients. First, it lets you select an option to not include all public folders, making downloads faster. Second, to avoid some IMAP4 clients' requirement of reporting message size, Exchange's Fast Message Retrieval option approximates message sizes, reducing the transaction overhead and making downloading faster.

Version 5.5 adds support for the intelligent referrals found in LDAP 3, which pass a user to another LDAP directory if the requested mail address is not contained in the originally queried directory.

Microsoft's purchase of Linkage Software should enable dramatic improvements in enterprisewide connectivity for Exchange, and ease customers' struggles with connectivity and coexistence for legacy messaging systems. With new Notes, PROFS and SNADS connectors, Exchange will cover those needs better. The connectors provide message conversion and exchange, as well as directory replication. Exchange does not yet have a GroupWise connector, but does offer a GroupWise migration tool.

However, only the Notes connector was in the Release Candidate 1 code. In testing, I noticed that the Notes connector's installation, configuration and ongoing administration is separate from and bears little resemblance to either the MS Mail or the cc:Mail connector. In addition, the Notes connector is administered from a completely separate Exchange Connectivity Adm inistrator utility that is started independently from the Exchange Administrator.

The long-awaited, 16-bit Outlook client for Windows 3.x and the Outlook Macintosh client also improves Exchange's enterprise reach. Both have better memory management to improve performance and are fully compatible with Windows95's calendaring feature.

Managing It All Customers have long demanded the ability to restore a single user's mailbox without the administrator having to restore the entire message store. Exchange 5.5 offers a novel twist on this old dilemma in Deleted Item Recovery. In the lab, deleted messages remained on the server--marked as hidden--for a specified period, so I could recover them. I like the fact that this feature is user-driven, freeing administrators to concentrate on other tasks. The feature involves both the administrator, who establishes the number of days that deleted items will be retained, and the user, who initiates the recovery process from within the Deleted Items folder of Outlook 8.02 or higher. I liked the option the administrator has of not permanently purging any deleted items until the store has been backed up.

This release offers SNMP support of the Madman (Mail and Directory Management) MIB for use with SNMP management consoles. Exchange now sends SNMP event notifications to any SNMP-compliant system.

Nancy Cox can be reached at ncox@nwc.com.