 Proxy Servers are software that act as intermediaries between client and servers on the Internet.  They help users on private networks get information on the Internet when they need it while maintaining network security.  They also store frequently requested information such as web pages.

normal proxy-less web transaction :

web transaction that uses a proxy server

Mechanical Proxy

Application Proxy

 Firewall Proxies: Internet Trusted Systems Firewall

 HTTP Proxy: › A HTTP Proxy server is one which is used to handle HTTP client requests. › It acts as an intermediary between the HTTP client browser and the remote web server. › It behaves as a server when it accepts documents from the client and acts as a client to remote web servers when it’s cache doesn’t have the requested documents.

 FTP Proxy:  controls FTP traffic sent by the FTP server.  FTP proxy controls unwanted requests and attacks by limiting the number and type of FTP commands that a user is allowed to send FTP proxies.  specify whether or not files can be downloaded or designated as “read only”.

 Security: › filtering requests, both incoming and outgoing, › keep users out of visiting particular websites based on URL addresses or to prevent others from gaining access via IP address authentication. › scan data for viruses or inappropriate words.

 Security  Conserve Bandwidth › improve performance (PROXY Caching) As they scan data, proxies can determine which data should be stored in cached memory so that they can later be used for immediate access. How old are the proxy server's pages ?

 Availability of Software  Limited Virus Protection  Anonymity Abuse

 Limited Access  Configurability  Compatibility

proxy servers provide extensive logging and reporting

 Filtering certain type of file  Filtering specific beginning and ending HTML tags from Web pages  Defining a "deny" or "allow" list of URLs  Virus checking

 productive use of company resources   Preventing data theft  Sharing connection with others  Filtering the content for children and teens

 Planning  Implementing  Verifying

To use a proxy server, the browser must be told the identity of the proxy server and which of the various types of web request should use the proxy…  proxy automatic configuration file  manual configuration

 Suppose you are surfing the Web.  You don’t want Web site to know your IP address  And you don’t want your ISP to sniff your traffic.  Possible solution: use anonymizing proxy