31. Configure Proxy Server Settings  BEFORE YOU BEGIN 30 Configure Networking Manually
 SEE ALSO 33 Share Your Internet Connection 34 Configure a Secure Tunnel (VPN)
In some network configurations, you might have to set up proxies , which are intermediary computers that sit between your computer and the outside network.  KEY TERM Proxy An "intermediary" computer that sits between your computer and the outside network, usually in order to increase access speed to common sites.
Proxies can serve many purposes, but the most common is to speed up access to commonly used data. A proxy does this by posing as the server to which you need to connect, and then sending your request on to the remote server itself. The proxy then saves the information that comes back in a cache, as well as passing it on to you. If you (or another computer) tries to access that same information again, the proxy can simply send back the information it already has, rather than sending out another request for the same data from the remote server. This arrangement saves time and bandwidth, particularly on slow Internet connections. 31. Configure Proxy Server Settings 
Most proxies are found in university or corporate networks, for the benefit of the students or employees . If your network administrator provides the addresses of proxy servers, you will need to set up your Mac to use them. You can configure proxies for many different network services, including HTTP, FTP, and email. Each kind of proxy is configured by simply specifying an IP address (and, optionally , a port number), as well as a password if the proxy is password-protected. | 1. | Select Network Device On the Network Preferences pane of the System Preferences , select Network Status from the Show menu. Double-click the network device you want to configure. Alternately, select the device from the Show drop-down menu. NOTE You can configure any of your available network devices to use proxies; however, you will need to configure the proxies for each such device separately. | | 2. | Open the Proxies Screen
Click the Proxies tab to open the screen where you can configure the device's proxy settings.
| | 3. | Select the Proxy Type
The Select a proxy server to configure box lists the many proxies you can configure. The most commonly used proxies are Web Proxy (HTTP), FTP Proxy (file transfer), and Mail Server Proxy (email); ask your network administrator which proxies you should set up, and what proxy addresses you should use for each one.
| | 4. | Specify Proxy Server and Port
After selecting a proxy type from the Select a proxy server to configure box, enter the IP address of the proxy in the Web Proxy Server field to the right. If the proxy uses a numeric port, enter the port number in the field after the colon . (Your office's network administrator or your Internet service provider has this information.)
| | 5. | Enter a Proxy Password
If your proxy server requires a password, select the Proxy server requires password check box; a sheet appears that prompts you to enter an account name and password for the server. Enter this information and click OK .
If you ever have to change the account name and password after you've configured the proxy, click the Set Password button to retrieve the password sheet.
| | 6. | Disable and Enable the Proxy
After you have configured a proxy, you can disable and enable it without losing its configuration (if, for instance, you need to do some task that doesn't work through a proxy). In the Select a proxy server to configure box, select or deselect the check box next to the proxy you want to use or bypass.
| | 7. | Enter Exception Hosts
Some hosts on the network might be incompatible with proxies, or you might want to exempt them from using the proxy. This is a common practice for telling your Mac what machines are on your home network, so it can connect to them directly rather than going through the proxy. You can do this by listing the hostnames in the Bypass proxy settings for these Hosts & Domains box at the lower left. List the hostnames one per line or separate them with commas.
| | 8. | Apply Proxy Settings
Click the Apply Now button to apply the proxy settings; the settings do not take effect until you click this button.
From now on, each time you connect to any of the services for which you have configured proxies (the Web, an FTP site, email, and so on), the computer will connect to the proxy instead of directly to the specified site. On subsequent times that you access the same site, access to the data should be much faster and more reliable than without the proxy.
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