Hi,
I used the feature of ols to setup the hotlink protection as follows,
hotlinkCtrl {
allowedHosts mysite.com www.mysite.com foo.com
enableHotlinkCtrl 1
suffixes jpeg, jpg, png, gif, svg, tiff, bmp, webp, bpg, css, ico, js, woff, woff2, ttf, ttc, otf, eot...