Proxying to ip-camera

[wishmaster]

Hi,

I have the web site and would like to proxying all requests to /ipcam location to internal ip-camera.

website http://site.com
ip-cam http://site.com/ipcam

Below config:

location /ipcam {
                proxy_pass http://192.168.20.99:80/;
                proxy_redirect off;
                proxy_set_header Host $host:$server_port;
                proxy_set_header X-Real-IP $remote_addr;
        }

All works fine, but ip-cam can not determine UA and therefore I gets broken login page and unable to login. 

Below the error log from console:

ReferenceError: Browser is not defined
if(!(Browser.ie7 || Browser.ie8)){

With port redirection by firewall all works fine.

Is anybody can help me. IP-camera - Dahua.

--
Vitaliy