http://www.wired.com/news/news/technology/story/20493.html [snip..] Back Orifice 2000 also promises to be a great deal more difficult to detect than its predecessor because it enables users to configure its port setting. Previously, intrusion detection and antivirus programs could detect Back Orifice because it used a default port setting of 3113. [snip..] [Default port on Back Orifice was 31337.]