You know you're in for a "fun ride" when you find that's there's hidden ports and processes on your Linux systems. So how do you find out? Unhide a tool that will help. It does that by comparing the contents of /proc with the output of the 'ps' command; by doing syscall scanning, and looking at PID space.
If you've got Ubuntu or Debian systems then you can install unhide using your favorite package manager. Or grab a copy directly from the tool's Web site.