Comcast now is trying to cut off spammers before they unleash torrents of junk e-mail.
The operator in the third quarter deployed a "sender reputation" service from San Francisco-based Cloudmark to pinpoint potential spammers. Comcast has already been using the Cloudmark Authority system to protect the 25 million e-mail accounts it hosts from spam, viruses and phishing attacks.
Terms of the expanded deal were not disclosed. Comcast, the nation's biggest cable operator, had 15.3 million high-speed Internet customers as of the end of June.
Cloudmark's Sender Intelligence includes data regarding spam resulting from bot infections on Comcast's network, and serves as a component of the MSO's new Constant Guard security program.
The Cloudmark sender-reputation service uses data from multiple sources. In addition to analyzing traffic patterns, the system incorporates user feedback and spam-correlation statistics to calculate sender reputation scores "in near-real-time," the company claims.
Cloudmark's customers include Cox Communications, Cablevision Systems, EarthLink and Swisscom.