For many types of work and school Internet connections, a proxy server is used when you get online. This is used for increased security, because it is the proxy server, not your own computer, that sends your connection requests to the Internet. Proxy servers also prevent computers on a network from visiting unauthorized sites. Examine your computer's Internet Options to find the address of the proxy server your computer is using.
Finding the Proxy Server in Windows
Click "Start," then "Control Panel."
Double-click "Internet Options." If you do not see this option, click "Classic View" in Windows XP and Vista or "View by: Small icons" in Windows 7.
Click the "Connections" tab, then the "LAN Settings" button. The address and port number for the proxy server used by your computer are shown in this window.
Click the "Advanced" button. If different proxy servers are used for different protocols such as HTTP and FTP (this is not common), they are shown here.
Finding the Proxy Server in Mac OS X
Click the Apple icon, then "System Preferences."
Click the network adapter that is in use, then click "Configure."
Click the "Proxies" tab. If your computer is configured to connect to the Internet through a proxy server, the server address and port number are shown here.