Differences Between Regular and Undetectable Proxies
There are plenty of proxies to choose from today, but not all proxies offer the same protection. Some proxies are little more than relays, offering no extra protection whatsoever. Even some so-called anonymous proxies still announce themselves and volunteer some information via HTTP headers.
Three headers can identify a proxy (and you) to a host. These headers are:
- HTTP_X_FORWARDED_FOR identifies your IP address as the source of traffic.
- HTTP_VIA identifies the proxy’s IP address and software used.
- REMOTE_ADDR can be either your IP address or that of the proxy (see below).
As mentioned, proxies can behave in various ways, and some are more secure than others. We can see from these headers that a proxy acting merely as a relay offers no privacy protection. A relay proxy will divulge your IP address in the HTTP_X_FORWARDED_FOR and possibly the REMOTE_ADDR header. Additionally, a standard proxy will identify its usage through the HTTP_VIA header, letting the host know that you are using a proxy.