Not a member of Pastebin yet?
Sign Up,
it unlocks many cool features!
- Anonymity of Proxy
- The exchange of information in Internet is made by the "client - server" model. A client sends a request (what files he needs) and a server sends a reply (required files). For close cooperation (full understanding) between a client and a server the client sends additional information about itself: a version and a name of an operating system, configuration of a browser (including its name and version) etc. This information can be necessary for the server in order to know which web-page should be given (open) to the client. There are different variants of web-pages for different configurations of browsers. However, as long as web-pages do not usually depend on browsers, it makes sense to hide this information from the web-server.
- What your browser transmits to a web-server:
- a name and a version of an operating system
- a name and a version of a browser
- configuration of a browser (display resolution, color depth, java / javascript support, ...)
- IP-address of a client
- Other information
- The most important part of such information (and absolutely needless for a web-server) is information about IP-address. Using your IP it is possible to know about you the following:
- a country where you are from
- a city
- your provider?s name and e-mail
- your physical address
- Information, transmitted by a client to a server is available (accessible) for a server as environment variables. Every information unit is a value of some variable. If any information unit is not transmitted, then corresponding variable will be empty (its value will be undetermined).
- These are some environment variables:
- REMOTE_ADDR ? IP address of a client
- HTTP_VIA ? if it is not empty, then a proxy is used. Value is an address (or several addresses) of a proxy server, this variable is added by a proxy server itself if you use one.
- HTTP_X_FORWARDED_FOR ? if it is not empty, then a proxy is used. Value is a real IP address of a client (your IP), this variable is also added by a proxy server if you use one.
- HTTP_ACCEPT_LANGUAGE ? what language is used in browser (what language a page should be displayed in)
- HTTP_USER_AGENT ? so called "a user?s agent". For all browsers this is Mozilla. Furthermore, browser?s name and version (e.g. MSIE 5.5) and an operating system (e.g. Windows 98) is also mentioned here.
- HTTP_HOST ? is a web server?s name
- This is a small part of environment variables. In fact there are much more of them (DOCUMENT_ROOT, HTTP_ACCEPT_ENCODING, HTTP_CACHE_CONTROL, HTTP_CONNECTION, SERVER_ADDR, SERVER_SOFTWARE, SERVER_PROTOCOL, ...). Their quantity can depend on settings of both a server and a client.
- These are examples of variable values:
- REMOTE_ADDR = 194.85.1.1
- HTTP_ACCEPT_LANGUAGE = ru
- HTTP_USER_AGENT = Mozilla/4.0 (compatible; MSIE 5.0; Windows 98)
- HTTP_HOST = www.webserver.ru
- HTTP_VIA = 194.85.1.1 (Squid/2.4.STABLE7)
- HTTP_X_FORWARDED_FOR = 194.115.5.5
- Anonymity at work in Internet is determined by what environment variables "hide" from a web-server.
- If a proxy server is not used, then environment variables look in the following way:
- REMOTE_ADDR = your IP
- HTTP_VIA = not determined
- HTTP_X_FORWARDED_FOR = not determined
- According to how environment variables "hided" by proxy servers, there are several types of proxies
- Transparent Proxies
- They do not hide information about your IP address:
- REMOTE_ADDR = proxy IP
- HTTP_VIA = proxy IP
- HTTP_X_FORWARDED_FOR = your IP
- The function of such proxy servers is not the improvement of your anonymity in Internet. Their purpose is information cashing, organization of joint access to Internet of several computers, etc.
- Anonymous Proxies
- All proxy servers, that hide a client?s IP address in any way are called anonymous proxies
- Simple Anonymous Proxies
- These proxy servers do not hide a fact that a proxy is used, however they replace your IP with its own:
- REMOTE_ADDR = proxy IP
- HTTP_VIA = proxy IP
- HTTP_X_FORWARDED_FOR = proxy IP
- These proxies are the most widespread among other anonymous proxy servers.
- Distorting Proxies
- As well as simple anonymous proxy servers these proxies do not hide the fact that a proxy server is used. However a client?s IP address (your IP address) is replaced with another (arbitrary, random) IP:
- REMOTE_ADDR = proxy IP
- HTTP_VIA = proxy IP
- HTTP_X_FORWARDED_FOR = random IP address
- High Anonymity Proxies
- These proxy servers are also called "high anonymity proxy". In contrast to other types of anonymity proxy servers they hide a fact of using a proxy:
- REMOTE_ADDR = proxy IP
- HTTP_VIA = not determined
- HTTP_X_FORWARDED_FOR = not determined
- That means that values of variables are the same as if proxy is not used, with the exception of one very important thing ? proxy IP is used instead of your IP address.
- Summary
- Depending on purposes there are transparent and anonymity proxies. However, remember, using proxy servers you hide only your IP from a web-server, but other information (about browser configuration) is accessible!
Add Comment
Please, Sign In to add comment