Not able to serve different robots.txt for CDN77

Question

We are trying to implement CDN77 in wordpress with genesis framework and want to serve different robots.txt for CDN. We used the following code

RewriteEngine On
RewriteCond %{HTTP:VIA} !^.*\.rsc.cdn77.org$ 
RewriteRule ^robots\.txt$ robots_cdn77.txt [L]

Our website is https://example.com and we have added a CND CNAME for https://cdn.example.com

We are facing the issue that our main robots.txt is getting rewritten alongwith the robots.txt for CDN website. Both robots.txt become same for above links. Both https://example.com/robots.txt and https://cdn.example.com/robots.txt serve the same resource.

How would I change the rewriterule such that each link serves their own robots.txt instead?

Answer 1

I would suggest you to setup a rule in CDN configuration. Saying for example when https://example.com/robots.txt is requested before it contacts origin server it append something like /cdn/robots.txt once the response in received from origin server, serve it as /robots.txt it self. This is possible in akamai CDN. Not sure which one are you using.