What is Proxy Server ?

The proxy is used to link a LAN to internet.

All the computers in the LAN have a private IP.

So the proxy can share an IP (for example a WebSite) to all the LAN and it's better for a security question.

You can use a proxy server to do :

• Cache to optimize users surfing (weight, ttl etc..), if the user A go to a page consulted by User B the response time will be faster because of the connection that preceded).

• Filtering : to allow or deny connection on websites

(ex : acl exampleacl dstdomain .example1.com .example2.com

          http_access deny exampleacl)

• Authenfication (LDAP, Kerberos, NTLM, Basic Auth)

OSI Model : Layer7 : Application