In order to configure a web browser to connect to a proxy server, you need to have access to the browser's connection setting options. If the browser's connection setting options are grayed out, simply logging onto the computer with an administrator account may solve the problem. If it doesn't, and the browser's connection setting options are still grayed out even when you're logged on as an administrator, the problem likely lies with a group policy setting that needs to be changed.
Gaining Access to the Connection Setting Options for Internet Explorer
Log onto the computer using an administrator account.
Video of the Day
Launch the "Group Policy" editor. In Windows XP, open the "Start" menu, click "Run," type "gpedit.msc" in the box and click "OK." In Windows 7 and Vista, open the "Start" menu, type "gpedit.msc" in the "Search" box, hit "Enter" on the keyboard, then select the group policy editor in the search results.
Navigate to the "Network Connections" folder. Click the plus sign next to "User Configuration" in the left side window panel, click the plus sign next to "Administrative Templates," click the plus sign next to "Windows Components," click directly on the "Internet Explorer" folder.
Locate and double-click on the setting for "Disable Changing Proxy Settings" in the right side window panel. Make sure "Disabled" or "Not Configured" is selected. When this setting is enabled, the "Use Proxy Server for LAN …" check box is grayed out, in addition to the "Address" and "Port" field boxes.
Locate and double-click on the setting for "Disable Changing Connection Settings" in the right side window panel. Make sure "Disabled" or "Not Configured" is selected. When this setting is enabled, the "Dial-up and Virtual Private Network Settings" are grayed out, the "Choose Settings if you need to configure a proxy server for connection" settings are grayed out, and the "LAN Settings" button is grayed out.
Configuring Internet Explorer to Connect to a Proxy Server
Launch Internet Explorer.
Select "Internet Options" from the "Tools" menu. Go to the "Connections" tab and click the "LAN settings" button.
Place a check mark in the box next to "Use a proxy server for your LAN" (these settings will not apply to dial-up or VPN connections).
Type the proxy server's IP address in the "Address" box. Type the port number the proxy server uses in the "Port" box.
Click "OK" to save settings. Click "OK" again to close the Internet Options dialog box.