Elite Proxies (Level 1)
Elite Level 1 Proxies, also called High Anonymity Proxies, provide the very highest level
of anonymity. With this type of proxy, the server you connect to receives no information
about your actual IP address. In fact, it cannot even detect that the connection was made
through a proxy.
Anonymous Proxies (Level 2)
Level 2 Anonymous Proxies, also called Distorting proxies, provide a degree of anonymity
acceptable for many purposes. Like Level 1, this Anonymous proxy hides your IP address
from a target server; but the server will recognize that a proxy is making the connection.
That's because a Level 2 proxy sends through some information – such as the Via header
omitted by Level 1 proxies.
A proxy is anonymous as long as the headers do not include your actual IP address. Keep
in mind that some server administrators restrict proxy requests. But restriction is based
primarily on log analysis, and it can be offset by rapid proxy rotation, with a new IP chosen
at random for each request.
Transparent Proxies (Level 3)
Level 3 Transparent proxies do not hide your IP address from a server you are connecting
to, so it does not provide anonymity. Although your address may not be immediately
obvious, it's easy to find it out. Requests from transparent proxies pass in the proxy's IP
address in the Via header and your IP address in the X-Forwarded-For header.
These proxies, also known as Caching proxies, can be useful for caching data and for
speeding access to a list of frequently visited websites.