Transparent Proxy
Transparent Proxy is an ordinary proxy server that leaves any of your online privacy unchanged.
Transparent Proxy makes it possible to cache frequently accessed pages. As the result, access is speeded up and the user’s download time is reduced. Transparent Proxy is also used for filtering purposes.
To form a clear picture of a transparent proxy, see what values are given to the HTTP headers:
REMOTE_ADDR = Proxy’s IP address
HTTP_VIA = Proxy’s IP address
HTTP_X_FORWARDED_FOR = Your real IP address
Note that _X_ in the name of the variable means that its usage is optional. This variable can be absent from the header. However it’s considered good form in the internet to send HTTP_X_FORWARDED_FOR. This variable is supported by such proxy leaders as Squid, Apache mod-proxy, Cisco Cash Engine and others.
Anonymous Proxy
Anonymous Proxy provides more privacy besides the caching benefits of a transparent proxy. Your IP address is replaced by either the proxies’ IP, or a random address.
HTTP_X_FORWARDED_FOR variable is not sent to host; therefore your IP address cannot be logged.
An anonymous proxy can be displayed in the following way:
REMOTE_ADDR = Proxy’s IP address
HTTP_VIA = Proxy’s IP address
HTTP_X_FORWARDED_FOR = Proxy’s IP address or a random IP
There appears a rather interesting case when the value of HTTP_X_FORWARDED_FOR variable is substituted by an address that is unused in the internet but not empty (not deprived of value). For example,
127.0.0.1 – inner loop
192.168.X.X – local subnet, etc.
In this case, the field is formally filled in, but it doesn’t contain any information allowing the real user identification.
Working with an anonymous proxy, it’s important to make sure that HTTP_X_FORWARDED_FOR is substituted in the right way. Note that this variable can accumulate values of all proxies’ addresses by which a packet was sent. All addresses will be then stored in the variable comma-separated.
Elite Proxy
Elite Proxy is also called a high anonymous proxy as it provides the best security. It can’t be detected in any way: with an elite proxy your use of the Internet looks as if no proxy is used.
HTTP_X_FORWARDED_FOR, HTTP_VIA and HTTP_PROXY_CONNECTION variables are not sent by elite proxy-servers. The very fact of using a proxy remains unknown to host, let alone your IP address.
There is only REMOTE_ADDR header with the IP address of the proxy server, displaying the proxy server as the client. The use of the proxy could still be suspected if the client sends packets with a cookie from the previous “low-anonymous” visit. This problem can be solved by clearing cookies and sometimes the cache.
An elite proxy sends the following information:
REMOTE_ADDR = Proxy’s IP address
HTTP_VIA = blank
HTTP_X_FORWARDED_FOR = blank