Stopping hotlinking from subdomains

Question

We serve images from both our www. and img1/2/3 subodmains. The rule we have successfully blocks hotlinking from the www. but not the img1/2/3. Two part question: Why do the img1/2/3 not work when the www does and is there a way to economize this into one rule?

RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?domain.org [NC]
RewriteCond %{HTTP_REFERER} !^http(s)?://(img1\.)?domain.org [NC]
RewriteCond %{HTTP_REFERER} !^http(s)?://(img2\.)?domain.org [NC]
RewriteCond %{HTTP_REFERER} !^http(s)?://(img3\.)?domain.org [NC]
RewriteRule \.(jpg|jpeg|png|gif)$ - [NC,F,L]

Thanks a lot.

Answer 1

You need to use the OR flag in the first three conditions or, alternatively, collapse the three conditions into one.

OR flag:

RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?domain\.org [NC,OR]
RewriteCond %{HTTP_REFERER} !^http(s)?://(img1\.)?domain\.org [NC,OR]
RewriteCond %{HTTP_REFERER} !^http(s)?://(img2\.)?domain\.org [NC,OR]
RewriteCond %{HTTP_REFERER} !^http(s)?://(img3\.)?domain\.org [NC]
RewriteRule .(jpg|jpeg|png|gif)$ - [NC,F,L]

Collapse into one condition

RewriteCond %{HTTP_REFERER} !^http(s)?://((www|img(1|2|3)\.)?domain\.org [NC]