Zombie Machines, Port Blocking, Confusion And Large Bills

With the incredible rise of zombie machines that spew spam messages constantly, it looks like different ISPs continue to take very different approaches to dealing with the problem. As expected, Comcast has now started selectively blocking port 25 on accounts from that appear to be compromised. However, others are taking more extreme approaches. Over in the UK, NTL has apparently decided to just start blocking a variety of ports on all their customers without warning. This was exactly what Comcast had realized not to do - since they knew the support costs from angry and confused users would not be worth it. In the case of NTL, it sounds as if some of their support people don't even know what's going on, which is causing even more problems when users call in. Up in Canada, the story is a bit different. It sounds like most Canadian providers have reasonable plans for dealing with zombie machines - including a hybrid approach of sending warnings to subscribers who appear to have been compromised, blocking ports on just those users, or cutting them off completely if they don't respond. Most have dedicated support staff whose job it is to help clean up machines. The article reports, though, that some corporate users who don't have unlimited bandwidth are discovering that their providers aren't informing them - leading to shocking large bandwidth bills. They point out that their service providers should have let them know as soon as they noticed something out of the ordinary, but so far the providers haven't been particularly forgiving (leading at least one company to declare bankruptcy).