Customer Stories


Rackspace logo

Requirement for an accurate and scalable messaging abuse solution due to growth of business and rise in spam volumes.

"[Our] mission is to be the best hosted business-class email provider and partnering with Cloudmark furthers this goal." — President Mailtrust (now Rackspace)

View the customer story to learn more.



  1. Overview
  2. Profile
  3. Business Challenges
  4. The Cloudmark Solution
  5. Results



Rackspace Email & Apps


Hosting Provider

Business Challenge

Required an accurate and scalable messaging abuse solution due to growth of business and rise in spam volumes.

Cloudmark Solution

Cloudmark Authority for SpamAssassin


  • Decrease in spam, phishing, and viruses
  • Better predictability in resource planning.
  • Increased customer satisfaction


Rackspace Email & Apps, formerly Mailtrust, provides business-grade email hosting to more than 100,000 companies. The rapid customer growth coupled with the rise in spam volume, resulted in a strain on the company’s computer resources, which were increasingly dedicated to anti-spam and anti-virus filtering. While its previous spam filtering solutions were effective early on, as Rackspace Email & Apps grew, it required a more efficient approach to messaging security.

Business Challenges

The company sought a solution that would boost both filtering accuracy and message scanning performance, which would improve the overall user experience and decrease costs. Additionally, the optimal solution would enable it to leverage its existing open source Apache SpamAssassin platform.

The Cloudmark Solution

After evaluating several solutions, Rackspace Email & Apps selected the Cloudmark Authority plug-in for SpamAssassin.


Rackspace is seeing positive results from the deployment:

Improved filtering accuracy

With Cloudmark, Rackspace Email & Apps has achieved 98 percent accuracy in detecting and stopping all categories of spam and phishing with near-zero false positives. High accuracy is maintained by an in-memory cache of the latest threat fingerprints, which is updated by Cloudmark every 30 seconds.

Reduced server load and CPU usage

Because Cloudmark’s fingerprinting technology requires significantly less computing resources than alternative filtering solutions, Rackspace was able to cut the number of filtering servers it used by 50 percent and the reduction in CPU workload led to increased server performance overnight.

Time, power and resource savings

Rackspace has experienced significant savings on spam filtering infrastructure, power consumption and administration that are passed on to customers in the form of improved service and lower service charges. These improvements also enable administrators and engineers to re-focus their attention on email storage, availability and new products, rather than spam.

Finally, Cloudmark integrates seamlessly with Rackspace Email & Apps’ new integrated control panel, allowing customers to control both Exchange and Noteworthy email services from one central location, enabling a single domain with both types of mailboxes and one shared set of spam controls.