Callbook Service at port 2000 ?

Hi all, i am new with mikrotik and found this:

Full port scanning found Mikrotik port 2000 is open - It say “Callbook Service” is running, is that normal ?

What for Callbook Service is anyway ? How to close that port ?

it’s used by mikrotik bandwidth tester:

http://www.mikrotik.com/docs/ros/2.8/ip/service.frameset

thanks normis… :smiley: