Your web server is configured to run as a proxy server. In order to avoid abuse, it's recommended to restrict access to this proxy server. Open proxy servers are dangerous both to your network and to the Internet at large.
Running an open proxy is a high risk for the server operator. Such services are frequently used to break into foreign computer systems, child pornography is usually consumed through proxies, and illegal content is likely to be spread through such proxies.
You can control who can access your proxy via the <Proxy> control block as in the following example:
<Proxy *> Order Deny,Allow Deny from all Allow from 192.168.0 </Proxy>References
Apache module mod_proxy
Controlling access to your proxy