Comcast is continuing to evolve its online Constant Guard Protection Suite. The newest feature is DNC Lock, which helps prevent Comcast subscribers from connecting to fraudulent websites, according to a recent Comcast blog by Jim Janco, director of security and privacy for Comcast.

“To demonstrate how DNS Lock works, let's use as an example the holiday season,” Janco wrote. “Say you want to send an eCard for the holidays to your relative across the country. You type in the name of the well-known card company in the browser, and then enter things like your email address and the recipient's email address. In the main body of the card, you enter data like your phone number with a request to get together. If you're using Comcast's DNS Servers, then you can be confident knowing that you would actually be connected to this eCard company's Web servers (in technical terms, that the domain name you entered as the URL would resolve to the proper IP address of their Web server).

“However, if a cyber criminal changed your DNS Server, then it's possible that the domain name you entered would resolve to a fraudulent Web server, and the information that you entered could be stolen. In this case, the Constant Guard Protection Suite would prevent you from connecting to a non-Comcast DNS Server, and it would alert you if your DNS settings have been tampered with to help avoid this situation.”

Janco said that DNS was added to Constant Guard Protection Suite in response to new and emerging malware that could alter DNS settings on customers’ computers without their knowledge, which makes them susceptible to fraud. DNS Lock can be manually turned off by Comcast subscribers should they decide to use a different DNS service.

Constant Guard is Comcast's umbrella brand name for its security and safety features that are included with the company's Xfinity Internet service.

Comcast’s Constant Guard program was first trialed in Denver in 2009. At the time, it included a bot detection and notification service before Comcast added other online protection features such as identity theft protection. Constant Guard was rolled out across Comcast’s entire footprint last year.

Earlier this year, Comcast added Norton Security Suite Version 6 to Constant Guard at no additional cost.