I've got a system where I need customers to do something like set a CNAME on a subdomain, e.g. site.domain.com, which forwards to output.mydomain.com. The site it refers to needs to output specific data based on the originating domain.
Can PHP's HTTP_REFERER be used reliably? I heard that this could possibly not be the case as it's browser dependent... So what should be used?
Would it be better to attempt to implement a system using wildcards and htaccess, where the client is directed to point their site.domain.com website at customer.output.mydomain.com?