If you are using proxy on your network and want to know its IP and port, type:

reg query "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings" | find /i "proxyserver"

You can also get the automatic configuration file URL from the registry by running:

reg query "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Wpad" /s | find /i "WpadDetectedURL"