I've had two different instances of them put on this system in the last 3 days. I know this because I have chkrootkit installed and I read the email chkrootkit generates. The last install of packet sniffer didn't take more than an hour to accomplish either. Other than removing dhclient and reinstalling it and changing all passwords on the system what else needs to be done to get a better control over this problem. I leave the system on and logged into a user account only since I'm downloading podcasts with it during the day while I'm away from the system.