Why won't apache let me in?

Question

Apache HTTP Server

At the root of the project is a file to which I restrict access via .htaccess (located in the same place), while allowing access from a specific ip:

<Files private.php>
order deny,allow
deny from all
allow from <ip>
</Files>

But when accessing from the specified ip, I get a 403 error. What could be the problem?
The server is running Apache 2.2

Answer 1

It turned out that apache is behind a reverse proxy. I solved it with this config:

SetEnvIF X-Forwarded-For "x.x.x.x" AllowIP
<Files private.php>
order deny,allow
deny from all
allow from env=AllowIP
</Files>