To set the proxy setting of Firefox:
- Open a Firefox browser.
- Click Tools > Options.
- Go to Advanced > Network > Settings.
- Ensure the Use system proxy settings option is ticked.
To set the system proxy for Windows 7:
- Click Start > Control Panel.
- Double-click Network and Internet.
- Double-click Internet Options.
- Go to Connections > LAN settings.
- Tick the Use a proxy server for your LAN (These settings will not apply to dial-up or VPN connections) checkbox and then enter the correct proxy server address and port number.
- Tick the Bypass proxy server for local addresses checkbox and then click OK.