Archiving External Messages
In our new, somewhat elaborate, SMTP environment, the archiving objective
becomes simpler. We already proved that with built-in Exchange features, we can
distinguish and, more important, reroute SMTP messages based on domain names.
Also, we know that message archiving is an optional IMC function. We concluded
that an additional IMC, dedicated to processing external messages, was our only
requirement.
Figure 2 shows that we added an Exchange server, Extmail, and outlines
configuration settings for the Our Firm site: We have two Exchange servers.
Intmail is home server to all Exchange mailboxes and Custom Recipients. The
Intmail IMC routes gw.ourfirm.com messages to the GroupWise SMTP gateway and all
other mail to Extmail. The message archival feature of Intmail's IMC is
disabled. We added Extmail to the site to send and receive Internet mail.
Extmail uses DNS to deliver messages to appropriate Internet mail hosts. We
configured Extmail to archive SMTP messages.
Again, let's trace the route of messages and their replies, to examine the
design. Assume we've already contacted our client's ISP to add an A record (DNS
terminology for the record that contains the IP address and fully qualified
domain name of a computer and that is used for name resolution) for Extmail and
to modify our MX record directing mail to Extmail.
Mail from an Exchange user, user@ourfirm.com, addressed to president@whitehouse.gov
leaves the Exchange site via Extmail's IMC, which is configured
with a global wildcard address space (*). Extmail uses DNS to find the
appropriate mail host for whitehouse.gov and transfers the message. Extmail
receives the reply, addressed to user@ourfirm.com, and subjects the
message to the criteria of imcroute.cfg (the IMC Sample Extension DLL
configuration file). If Extmail finds a match, the message is rerouted to the
local host and IMC handles it. After archiving the message, Extmail's IMC
delivers the message to the recipient's Exchange mailbox. No alternate recipient
is specified, so the users receive the message in their inbox.
A GroupWise message to Exchange is different from our previous model. The
message, from davej@ourfirm.com to user@ourfirm.com, reaches the GroupWise SMTP
gateway, which directs the message to Intmail. If the message matches the
criteria in imcroute.cfg, the message path is localhost, Intmail's IMC, and the
message will be delivered to Exchange (this path includes no message archival).
The reply is addressed to davej@ourfirm.com, which is a valid Exchange mailbox,
configured to reroute mail to davej@gw.ourfirm.com. Intmail's IMC, configured
with address space and message delivery options, transfers this reply to
gw.ourfirm.com. The GroupWise SMTP gateway performs a directory lookup for davej
and passes the message to the user's mailbox.
Again, GroupWise messaging with the Internet is the best illustration of
our proposal. A message from davej@ourfirm.com to president@whitehouse.gov
travels through the GroupWise SMTP gateway to Intmail, doesn't match domain
criteria in imcroute.cfg, enters Intmail's IMC (isn't archived), is forwarded to
Extmail, doesn't match domain criteria in imcroute.cfg, enters Extmail's IMC,
and is archived and forwarded to the appropriate mail host for whitehouse.gov.
The reply to this message (to davej@ourfirm.com) follows an equally ambitious
route. From the whitehouse.gov SMTP host to Extmail (found via DNS lookup), the
message matches the criteria of imcroute.cfg, is rerouted to localhost, is
archived, and is delivered to Exchange by the IMC. Based on the alternate
recipient configuration (to davej@gw.ourfirm.com) of my Exchange mailbox, the
message then travels to Intmail's IMC, to the GroupWise SMTP gateway, and to my
GroupWise mailbox.
Complex but Effective
Although our messaging project was not simple, Exchange Server answered our
toughest challenges. We used NT's NetWare migration tool to create accounts and
Exchange's Directory Import feature and Microsoft Access to create mailboxes and
Custom Recipients. Within minutes after import file setup and sample runs, we
had a complete directory of all user mailboxes, hidden Custom Recipients, and
corresponding Windows NT accounts. Later, still using Directory Import and
Access, we effortlessly modified each mailbox to include items such as
department and distribution list membership.
Although industry regulations for message archival are not commonplace, our
solution can be practical in countless other scenarios. For example, although
our solution discusses migration from Novell's GroupWise, you can apply this
solution in migrations to Exchange from any mail platform that supports SMTP.
Also, to comply with the Federal Records Act, many government agencies retain
copies of electronic communications involving matters of public record. These
organizations can use parts of our solution to archive internal and external
mail. In today's world of business partner connectivity and increased online
vendor and customer correspondence, Microsoft Exchange has many options to
offer. Its flexibility, however, underscores the value of critical thinking
before implementation.