Comcast announced today that it has picked Cloudmark to protect its 15.3 million data subscribers and 25 million e-mail accounts from spam, viruses and phishing attacks.

Specifically, Comcast has deployed Cloudmark Sender Intelligence (CSI) to bolster its current Cloudmark Authority platform for increased protection against messaging threats.

CSI, which includes data regarding spam resulting from bot infections on Comcast's network, serves as a component of Comcast's new “Constant Guard” security program.

“Comcast’s deployment of Cloudmark Sender Intelligence is an important component of our recently launched Constant Guard security program, as well as our anti-abuse defenses for Comcast SmartZone, and reinforces our commitment to providing customers with the best and safest e-mail and Internet experience,” said Jason Livingood, executive director of Internet systems engineering at Comcast . “Cloudmark has enabled us to deploy accurate, constantly updated messaging-related security defenses that easily scale to protect millions of users, and which delivered an immediate ROI by reducing the burden of spam coming into our network.”

CSI and Cloudmark Authority provide cloud-based intelligence that combines timely and accurate reputation data on good, bad and suspect senders with message filtering capabilities. CSI analyzes traffic patterns, feedback and fingerprint correlation statistics to establish and adjust sender reputation scores in near-real time.

Data from CSI can be integrated into network perimeter devices to protect the messaging infrastructure against spam, phishing, zombies, botnets and advanced converged threats. Additionally, Cloudmark said CSI provides significant additive security coverage to existing DNS-based Blacklists (DNSBLs) and reduces potential false positives.