Proxy Server (http://en.wikipedia.org/wiki/Proxy_server)

• A server that serves the request of its clients by forwarding its request to other server
• Request may be the following:
  • file
  • connection
  • other resource
• Functions of proxy servers are:
  • Caching proxy server
    • can serve request without contacting the specified server because such content was already saved when it was first requested.
  • Web proxy
    • it mainly focus on WWW traffic to deny or approve such URL
  • Content Filtering Web Proxy
    • it controls internet access for designated or specific users
      
  • Anonymizing proxy server
    • it anonmyzes user that will make him hard to trace
  • Hostile proxy
    • used to eavesdrop on a targeted data, commonly used by criminals
  • Intercepting proxy server
    • also known as transparent proxy
    • it is used to prevent avoidance of acceptable use of policy
  • Transparent proxy server
    • does not modify the request
      
  • Non-transparent proxy server
    • does modify the request
  • Forced proxy
    • It intercepts TCP connections and HTTP (so what’s the difference?)
      
  • Open proxy server
    • It can be accessed by any Internet user
    • It is used to store and forward internet services such as DNS and or web pages to reduce bandwidth

  • Closed proxy
    • It is only accessible to a specific user
  • Split proxy server
    • Implemented as two programs on two different computers to speed up data transmission.
      
  • Reverse proxy server
    • Also called as surrogate
    • Used in front of web server
    • It dispatches in-bound traffic to a set of servers
    • It can be used for load balancing a cluster of web servers
      
    • In contrast, forward proxy act as a proxy for out-bound traffic
    • Some of the reasons for installing a reverse proxy server are the ff:
      • Security
      • Encyption / SSL acceleration
      • Load distribution
      • Caching static content
      • Compression
      • Spoon feeding
        
  • Circumventor
    • a method of defeating blocking policies implemented by using proxy servers
    • It can be used by people who have been blocked by a website
    • If used by an untrusted third party with malicious intention, personal information while using a circumventor maybe compromised