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IMF Tune - Bringing Back the Exchange Connection Filter
IMF Tune - Bringing Back the Exchange Connection Filter

Case Study: CNF Incorporated

January 19, 2006

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Like any major corporation, CNF Inc, a $4.2 billion global transportation, logistics and supply chain services organization, is continually challenged to protect its email networks against rising volumes of spam and increasingly ingenious spam attacks. As part of its overall strategy, CNF chose WinDeveloper IMF Tune as a key element in its protection program.

CNF is using IMF Tune to effectively harden its anti-spam protection. Fully integrated with CNF's Exchange environment, the multi-layered, heterogeneous spam filtering configuration spans a mix of Red Hat Enterprise and Windows platforms. The combination of anti-spam and open integration features offered by IMF Tune enabled maximizing filtering effectiveness.

The Challenge

At CNF, the Exchange organization services over 10,000 mailboxes across 18 mailbox servers. The Internet-facing servers run Red Hat Enterprise. These deliver the email traffic to/from the internal Windows network running Microsoft Exchange. From all over the globe, users connect to the CNF data centers to access their mailboxes.

With an email load from the Internet reaching 200,000 per day, such a network certainly cannot permit spam to hamper user productivity. Thus CNF demanded highly effective spam filtering, but which leverages the native Exchange 2003 anti-spam functionality for a seamless user experience.

Before adopting IMF Tune, CNF deployed a signature-based anti-spam solution running on Red Hat Enterprise. This filtering was further hardened with the Intelligent Message Filter (IMF) at their Exchange bridgehead servers. Outlook 2003 client-side filtering finally contributes yet a third layer. The diversity in platforms meant that some emails identified as spam at the network edge were still being delivered to the user's Inbox.

Scott Bueffel, the Senior Messaging Administrator, described more issues necessitating resolution, "The IMF offers almost no configuration options. False positive rate is not zero, so some legitimate messages were being blocked. In addition, messages moved to Outlook's Junk E-mail folder are not differentiated from messages moved by Outlook's own engine."


IMF Tune's comprehensive feature set enabled CNF to effectively overcome all of these challenges. Its ability to integrate any anti-spam solution to Exchange, coupled with its major IMF functionality boost, rendered IMF Tune the key to unleash the full spam filtering potential.

Suspected spam identified on Red Hat Enterprise (via heuristic analysis) now is deposited to the Junk E-mail folder side-by-side with spam filtered by IMF and Outlook. Scott explains how this was achieved, "We use the SCL Management feature to look for a particular header and value so that we can forcefully set an SCL. This allows us to have all messages suspected of being spam, moved to the Junk E-mail folder."

As Scott points out, IMF Tune also made up for the lack of functionality within IMF. "We use IMF Tune's white listing feature to allow certain senders to be exempt from filtering. The logging feature gives us permanent statistics of the messages moved to the Junk E-mail folder. "

Tagging message subjects with the SCL rating is another feature enhancing administration and user experience, "It allows differentiating between emails filtered at the server from those filtered by Outlook. This also helps users understand why a certain message is in that folder.", continued Scott.

With such an email volume, CNF could not afford loss in performance or any sort of disruption. IMF Tune's lightweight design was thus highly appreciated. Scott gave his thumbs up in this area as well, "There is no impact to performance on the servers. IMF Tune functions without interfering with any other operations and changes made take effect immediately."

WinDeveloper Support Under Test

CNF did not limit itself to what the IMF Tune package offered. During their evaluation, CNF identified a potential shortcoming. The SCL subject tagging functionality could conflict with client-side rules configured in Outlook.

Once again the WinDeveloper team did not let Scott down. The required functionality changes were promptly included in the latest product update release. This is how Scott described WinDeveloper support, "Support has been wonderful. Responses are timely, courteous and helpful. Implementation of feature requests to-date has been quick. A company's values and business model are easily perceived based on its support and its relationship with its customers."

Cost Effective and Simple Licensing Model

With so many anti-spam product offerings, organizations have a broad product selection in front of them. "Price is excellent, especially considering the benefit gained. Pricing IMF Tune per server, instead of per mailbox or based on message volume, makes licensing easier.", Scott concluded.

IMF Tune is priced per server starting from $298 for a single server. Multiple server licenses can further benefit from discounts. More information is available from the WinDeveloper web site at From here a 30-day free evaluation version is available for download.

About WinDeveloper

WinDeveloper Software delivers applications and consultancy services for the Windows platform. WinDeveloper specializes in Microsoft Exchange integrated applications as well as other core Windows technologies. For details on our current consultancy projects and other products, visit our website,

About CNF

CNF Inc., a market leader in the transportation and supply chain management industry, is a $4.2 billion global enterprise with fast-growing, dynamic businesses and a long-established history. CNF's principal component companies - Con-Way Transportation Services, Menlo Worldwide and Vector SCM, operate in regional trucking, air and ocean freight forwarding, global logistics and supply chain management services, and trailer manufacturing. CNF has consistently been a service, sales and profit pacesetter and a benchmark stock (NYSE: CNF) on the Dow Jones Transportation Average for more than a quarter century.


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