Proxy Tutorial

**indri______jgc30@att.net** Fri Oct 19, 2007 9:53 pm

----- Proxies -----

Proxy servers
A proxy server is a kind of buffer between your computer and the Internet resource(s) you are accessing. The data you request come to the proxy first, and only then it transmits the data to you. A proxy server receives a request for an Internet service (such as a web page request) from a user. If the proxy server is also a cache server, it can use its local cache of previously downloaded web pages to provide the page without forwarding the request to the Internet. If the page is not in the cache, the proxy server uses one of its own IP addresses to request the page from the server on the Internet. When the page is returned, the proxy server relates it to the original request and forwards it to the user.

Why should I use proxy servers?
Security and privacy. Anonymous proxy servers hide your IP address saving you from vulnerabilities concerned with it. So you can safely surf the web and your information will never be used by hackers and spammers.
Speed improvement: Proxy servers accumulate and save files that are most often requested by thousands of Internet users in a special database, called cache. Therefore, proxy servers are able to increase the speed of your connection to the Internet. The cache of a proxy server may already contain information you need by the time of your request, making it possible for the proxy to deliver it immediately.
Sometimes you may encounter problems while accessing to web server when server administrator restricted access from your IP or even from wide IP range (for example restricting access from certain countries or geographical regions). You can try to access those pages using an anonymous proxy server.

What types of proxy servers exist?
There are several types of proxies. Proxy of each type is designed to solve its specific tasks, however they have much in common, and their abilities coincide in many features.

HTTP Proxy
HTTP proxy server is a proxy allowing to work on the Internet with HTTP and (not always) FTP protocols. It can carry out caching of information downloaded from the Internet.
Now HTTP proxy servers are the most widespread. Their support (ability to use them) is included into many programs: browsers, download managers etc. However, their support is not realized at a level of an operating system - in order to use them, you should configure all programs, which should use proxies, in an appropriate way. HTTP proxy servers have several anonymity levels.

SOCKS Proxy
SOCKS is a networking proxy protocol that enables hosts on one side of a SOCKS server to gain full access to hosts on the other side of the SOCKS server without requiring direct IP-reachability. SOCKS is often used as a network firewall, redirecting connection requests from hosts on opposite sides of a SOCKS server. The SOCKS server authenticates and authorizes requests, establishes a proxy connection, and relays data between hosts. There are two major versions of SOCKS: SOCKS4 and SOCKS5.

Anonymity of HTTP Proxy
â€¢Transparent - these proxies are not anonymous. They don't hide IP-address of a client and let a web server know that you are surfing through a proxy server. The task of such proxies, as a rule, is information caching and/or support of Internet access for several computers via single connection. Such proxies are not applicable for security and privacy while surfing on net. You can use them only for network speed improvement.

â€¢Anonymous - these proxies don't show your real IP but change the request fields so it is very easy to detect that you are using proxy.

â€¢High Anonymous - these proxy servers do not pass an IP-address of a client and don't send any variables indicating that you are using proxy server to host and look like real....