Should your ISP protect you from yourself?
Cox Communication has been attempting to help their customers by routing traffic destined for botnet controlled IRC servers to their own IRC servers. Many, if not most, of today's bots use IRC channels to allow botnet owners to control infected computers, a fact that Cox is trying to use to their customers' advantage by using DNS tricks to send requests destined for these control channels to their own servers. The Cox controlled IRC server then tries a number of commands to get the bot to uninstall itself. Even if this doesn't work, the fact that the bot running on a home system is connecting to Cox's IRC server rather than the bot herder's means that the bot will not get commands from the real IRC channel, effectively rendering it useless to the bot herder.
This is a slippery slope for Cox, but I'm not sure I completely disagree with it. While this sort of redirection can break a botnet, these networks are often using legitimate IRC servers for their control channels. So when someone tries to connect to a legitimate channel on the servers, they're effectively cut off due to the fake DNS information. This probably doesn't affect the majority of Cox's customers, professionals who rely on these IRC channels for communicating with their peers can be severely affected.
My real concern is where does this end? How much responsibility does an ISP need to take for the traffic from a home system? Traditionally, most ISP's are not much more than a conduit to get to the Internet. By taking the efforts necessary to block and clean up botnets on home computers, the ISP is taking a much greater role in the security of those systems. Will ISP's continue down this path, pushing additional security measures or will they be content with this level of control?
As long as ISP's are just acting on traffic traversing their networks, I think they're clearly acting within their rights. But sending traffic back to your computer that attempts to remove the bot is starting into a gray area. The next logical step would be to push anti-virus software to the computer. While this might be effective, it blurs the line of responsibility for the ISP.



