Apache uses. htaccess security chain course September 12, 2017 edit Shallow summer Cancel Follow follow private letter . htaccess security chain rule code: RewriteEngine on RewriteCond %{ HTTP_REFERER }! 4$ RewriteCond %{ HTTP_REFERER} ! Ahttp://(www.)? yourdomain.com/.*$ [NCI RewriteRule. (gif &line;jpg)$ http:// Www.yourdomain.com/Alternate image file name [RL]