Alright. Let me get this straight. They were performing a DoS (Denial of Service) through the DOS (Disk-based Operating System / MSDOS) PING command. From now on, I'll refer to Denial of Service as DoS (note the lowercase O) and DOS (the operating system) as MSDOS. They were using the MSDOS ping command to perform a DoS (Denial of Service) on the list servers.

Edit: This is fairly new to me, so I probably will make some technical mistake along the road here. Feel free to correct me if so.