Ever seen internet activity on your computer when you weren’t accessing the web? It could be something as simple as an installed program checking for updates, or as bad as malicious botnet code. Back in 2005, I asked Slashdot how to determine if my machine had become a zombie. They had some good tips, and my computer turned out to be okay. The linked article has specific instructions on how to use the ‘netstat’ command to find out which programs are accessing the internet. Well-designed rootkits will not show up on the list, of course, but other tools exist for those.