hotlink protection and IDM

hi , i have a question regardin hotlink protection and blocking internet download manager ( IDM ) direct link downloads .
when i enable hotlink protection , if i download a link using browser , it will work fine it will show a 403 forbidden for [f] flag or redirect for [r,nc] flag.

but when i copy that link to IDM , it can easily download and resume the file.
so , is there any easy solution for blocking IDM direct download links ? or i should just use php and session and cookies or use a database for saving download links and generate a random file name for each session of download to prevent idm ?

i have read that idm uses some specific header and i can block idm using that header details but i don't want to block idm for users that start downloading from site. i only want to block idm direct link downloads when the link is not entered from the allowed domain.

Web Hosting Talk - View Single Post - prevent direct file download but allow php download via htaccess

what do you suggest?