In comparison with the Microsoft Exchange or Outlook client, Web and POP3
clients have a passive relationship with Exchange: Such clients always request
information from the server. The server never updates them about changed
circumstances such as a new message. For this reason, Microsoft placed a Check
for new messages button in the Web client interface.
Although the new POP3 and Web clients are free or shareware, Microsoft
licensing policy clearly states that all clients must possess a Client Access
License (CAL) before they can connect to a server. The Microsoft Exchange and
Outlook clients are far more functional, so influences such as available
hardware or platforms drive the choice to deploy POP3 or Web clients. You'll
never get a Microsoft Exchange client running on a Solaris or Digital UNIX
workstation, but you can run Netscape. If you don't have large amounts of free
system resources on a low-end 386, a POP3 client such as Pegasus or Eudora Pro
will certainly let users communicate with everyone connected to Exchange.
Public Folder Replication
The Active Server melds Web resources with Exchange. The Internet News
Service lets feeds from Internet newsgroups come directly into a public folder,
or has Exchange act as a newsgroup server. Maintaining a single subscription to
a newsgroup and using public folder replication to distribute the information
will usually reduce the amount of data that Internet links must handle, so you
gain an immediate advantage. Also, using products like Fulcrum Find! for
Exchange or Verity's Search97, you can index anything in a public folder easily
for full text retrieval.
SMTP Support
Microsoft has renamed Exchange 4.0's capable Internet Mail Connector (IMC)
to Internet Mail Service (IMS) for Exchange 5.0 and bundles it with all variants
of Exchange server. The IMS can now act as a smart relay host and route new SMTP
messages that are presented to the IMS to other, non-Exchange destinations. This
point is important in large messaging environments where you typically operate a
single point of contact (in association with a firewall) between an enterprise
and the Internet. The single point of contact must be able to process messages
on behalf of other systems, routing them to their final destination. The
Exchange 4.0 IMC did not do this processing, so organizations had to operate
another computer, usually a UNIX system, in that role. Acting as a smart relay,
the IMS simplifies operations for all concerned.
SMTP mail systems are less functional (but easier to configure) than their
X.400 equivalents. ESMTP (Extended SMTP) is an attempt by the Internet
Engineering Task Force to close the gap, and Exchange 5.0 includes support for
RFC 1869 (Delivery Status Notification) and RFC 1870 (Notification of Message
Size). Knowing that a message has reached its destination is clearly important,
and Exchange can now fulfill that need if messages are sent to other SMTP mail
systems that support ESMTP.
Setting up IMS is easy with the Internet Setup Wizard. It looks as if the
Exchange engineers reviewed all the user complaints about the old IMC and
attempted to solve the problems by making sure that systems are configured
correctly. Anything that sorts out common problems, without a lot of effort from
systems administrators, is welcome.
Wait, There's More
Exchange 5.0 includes many other changes, so the new version fully justifies
the new version number (the number allocated to the new version went from 4.1 to
4.5, and then to Exchange 5.0, as Microsoft added new features). I'll highlight
a few of the more interesting ones.
The Administration program is now easier to use. Common properties (such as
the current logons to the server or the amount of space users occupy in their
mailboxes, as Screen 4 shows) are available with one click, and information is
generally available faster.
Corporate mail directories can rapidly become so large that knowing where
to look for someone is difficult. Exchange 5.0 supports address book views,
virtual containers in the directory that you can create based on different
attributes. For example, if you create a view based on the department
attribute, Exchange creates containers for each department, such as sales and
marketing.
A competent connector is now available for Lotus cc:Mail. To the cc:Mail
environment, the connector appears to be just another cc:Mail post office, but
the connector can seamlessly pass messages and directory information between
cc:Mail and Exchange. Interestingly, the cc:Mail connector also lets cc:Mail
users access any other connector Exchange operates, so cc:Mail users can use
Exchange to route messages to the Internet or X.400, without installing any
other gateways specific to cc:Mail.
Exchange 4.0 included migration utilities to help users of various mail
systems move their data to Exchange. Exchange 5.0 provides new migration
utilities for Netscape Collabra and Novell GroupWise. Some unsupported utilities
to help migrate UNIX sendmail-type systems are included in the new Microsoft
BackOffice Resource Kit for Microsoft Exchange.
The Exchange 5.0 RC1 requires NT 3.51 SP5 or NT 4.0 SP1. If you want to use
the Active Server to link Web clients, you need IIS 3.0 with the Active Server
components, which in turn requires NT 4.0 SP2. The final version of Exchange 5.0
will be out by the time you read this, and these requirements might change. If
your installation runs Exchange, I recommend you keep up to date with service
packs for Exchange and NT so you don't have quite so much work when you upgrade.
Beyond Exchange 5.0
The changes in Exchange 5.0 increase the power and flexibility of Exchange
as a messaging platform, chiefly by an impressively seamless integration of
numerous Internet protocols. Microsoft did not address the weaknesses of
Exchange 5.0 groupware capabilities, which make up Exchange's acknowledged
Achilles' heel in comparison to its major competitor, Lotus Notes. Exchange
electronic forms, for example, are still based in Visual Basic (VB), a language
that results in slow forms that you can execute only on a Windows platform. The
introduction of HTML in Exchange 5.0 and the impressive implementation of the
Web client provide a pointer to the future. Microsoft plans to replace VB forms
with platform-independent forms built around HTML and ActiveX components,
possibly by the end of 1997.
Microsoft sources say we can expect the next version of Exchange in late
1997. After all the work to accommodate Internet technologies in Exchange 5.0,
the focus of the next release will shift toward the demands of building very
large servers, those capable of supporting many thousands of users. Some
Exchange servers support thousands of users: Digital produces an Alpha server
that supports 2700 mailboxes. But the challenge is to scale up to 10,000 to
20,000 mailboxes. Changes (such as clustering) to achieve truly massive
scalability, the ability to support and manage a 16TB information store
(Exchange database), and the unification of the Exchange directory with the NT
Active Directory (NT 5.0) are needed from both Exchange and the operating
system. These developments will help corporate implementation teams, but require
a close eye on what's happening in Exchange and NT over the next few years.