Debugging WinPX

To debug the WinPX proxy installation, you can use the curl command-line tool, which is included with Windows 10 and later versions.

Open a Windows Command Prompt window and try executing the following commands.

First, let's check if you have a direct connection to the Internet:

curl --noproxy * --head http://example.com

The --noproxy * option tells curl to bypass any configured proxy. If the first line of the response starts with HTTP/1.1 200 OK, then you have a direct connection to example.com, and you may not need an intermediate proxy at all.

In a corporate network environment employing an enterprise proxy server, you are likely to receive an error message, such as:

• curl: (6) Could not resolve host: example.com
• curl: (7) Failed to connect to example.com:80 after 2047 ms: Could not connect to server

You can try to use the curl command with the --proxy option to specify the proxy server. For instance, if your enterprise proxy server is http://proxy.contoso.com:8080, you can try the following command:

curl --proxy http://proxy.contoso.com:8080 --head http://example.com

A typical response from the proxy server is HTTP/1.1 407 Proxy Authentication Required, which indicates that the proxy server requires authentication before allowing access to the requested resource.

To authenticate with the proxy server, the most secure option is Negotiate authentication (SPNEGO) using Kerberos. You can tell curl to use Negotiate authentication with the --proxy-negotiate option:

curl --proxy http://proxy.contoso.com:8080 --proxy-negotiate --head http://example.com

Running the above command, you should get the expected response HTTP/1.1 200 OK.

If some of your applications do not support Negotiate authentication or any of the proxy discovery protocols your company uses, you can use WinPX as an intermediate proxy server to forward the requests to the enterprise proxy server.

Start the WinPX proxy server by running the winpx.exe executable.

By default, WinPX will automatically configure itself based on the Windows proxy configuration. It will then listen for HTTP requests on the address http://127.0.0.1:3128.

Now, you can try the curl command again, but this time using the WinPX proxy server:

curl --proxy http://127.0.0.1:3128 --head http://example.com

Running the above command, you should again get the response HTTP/1.1 200 OK.

Compared to using the enterprise proxy server directly, WinPX automatically detects the Windows proxy settings, chooses the correct proxy server, and handles the proxy authentication for you.

Note that the address that WinPX listens on may differ from this example. To find out the actual proxy server address, you can open the WinPX Options dialog by double-clicking the WinPX icon in the Windows system tray. Then click the Copy proxy URL to clipboard button to copy the proxy URL to the clipboard.