This is a followup for this question.
When I used the proxy flag with mod_rewrite, I did not know all of its effects. Now I have two more problems, which need to be fixed!
The main problem is with user IP addresses, everyone appears to use the server IP. I can't trust http-x-forwarded-for because it is easy to forge headers, and the REMOTE_ADDR just shows the server IP.
I used the P flag because it acted as a mask, but Google loads everything with the actual URL.
How can I use this subdomain rewrite without the P flag? It needs to be internal.
Thank you for your help!