The stoker

hi guys this is my first post, apologies if its in the wrong sextion. i am using a macbook and got he angey ip scanner. when i am scanning it does pick up all the devices using my router, tablets, phones etc. But it does not pick up my xbox IP, and other IP's in my xbox live lobby (my friends etc) - am i doing something wrong or is it not able to find other xbox uers' IP? i am using a wired ethernet cable from my router to my xbox. many thanks for all your help.