Configuring WinPX

The GUI version of WinPX (winpx.exe) provides an options dialog that allows users to configure various settings for the proxy server. This dialog can be accessed by double-clicking the WinPX icon in the Windows system tray (usually located at the bottom-right corner of the screen, next to the Windows clock).

General Tab

This tab allows you to configure general settings for the WinPX proxy server.

Startup

• Automatically start WinPX app when I log in to Windows: This option allows WinPX to start automatically when you log in to your Windows account.
• Start proxy server when WinPX app starts: This option allows the WinPX proxy server to start automatically when the WinPX application is launched. If you prefer WinPX to run in the background without starting the proxy server immediately, you can leave this option unchecked.
• Set http_proxy/https_proxy environment variables to use WinPX: This option allows you to set the HTTP and HTTPS proxy http_proxy/https_proxy environment variables for your Windows account. Many applications, including command-line tools and programming languages such as curl or Python, can use these environment variables to route their network traffic through the WinPX proxy server.

Network

• WinPX network mode: This option allows you to specify the network interface that the WinPX proxy server will bind to. The available options are:
  • Loopback: In this mode, WinPX will only bind to the computers loopback network interface, i.e., the local network interface used for communication within the same device. The loopback adapter is typically represented by the IP address 127.0.0.1.
  • Loopback + WSL: In this mode, WinPX will bind to the computers loopback interface and also so the WSL2 network interface that is used to communicate to the WSL VM in NAT mode. If you configure the WSL network mode to Mirrored, the WSL VM can communication directly to the Windows hosts 127.0.0.1 addresss, and this option has no effect.
  • Any: In this mode, WinPX will bind to any network interface on your system, including public network interfaces. If the computers firewall settings permit it, this would make WinPX accessable from other computers on your network. You should only choose this option if you are aware of the security implications this option has.
• WinPX network port: This option allows you to specify the network port that the WinPX proxy server will listen on. The default port is 3128, but you can change it to any other available port if needed.
• WinPX proxy URL: This field contains the URL that you can use to access the WinPX proxy server. The URL is constructed based on the IP4 loopback address and the selected network port. For example, if you choose the Loopback network mode and use the default port to 3128, the URL will be http://127.0.0.1:3128. If you want other applications to use the WinPX proxy server, this URL is typically the one you would use in your applications proxy configuration.

Other

• Copy proxy URL to clipboard: This option allows you to copy the WinPX proxy URL to the clipboard so that you can easily paste it into other applications or configuration files.

Gateway Tab

Proxy gateway

These settings allow you to configure the proxy gateway that WinPX uses, i.e. the upstream proxy server in your network.

• Use Windows system settings: This is the recommended option for most users. Typically, your company will set the Windows system proxy settings as required for your network.
• Use Web Proxy Auto-Discovery (WPAD): This option allows WinPX to automatically discover the proxy settings for your network using the Web Proxy Auto-Discovery protocol.
• Use Proxy Auto-Config (PAC): This option allows you to specify a PAC file that contains the proxy configuration for your network.
• Use manual proxy settings: This option allows you to manually specify the proxy server address and port that WinPX should use as the upstream proxy. You should avoid this option if your company uses a PAC file or WPAD configuration, as not all servers may be reachable through the manually specified proxy server.
• No proxy (DIRECT): This option allows you to bypass any proxy server and connect directly to the internet. You should only use this option if you are sure that your network does not require a proxy server for internet access.

Security Tab

Proxy gateway authentication

These settings allow you to configure the authentication methods that will be used to authenticate at the proxy gateway.

• Allow Negotiate/Keberos authentication: Kerberos is the most secure authentication method and currently the recommended option for most users.
• Allow Negotiate/NTLM authentication: NTLM is a less secure authentication method and should only be used as a fallback if Kerberos is not available.
• Allow Digest authentication: Digest authentication is a moderately secure authentication method that uses a challenge-response mechanism to protect credentials.
• Allow Basic authentication: Basic authentication is an unsecure authentication method and should not be used. It transmits credentials in an unencrypted form and is vulnerable to interception.
• Username: Provides the username used for Basic authentication.
• Password: Provides the password used for Basic authentication.

WinPX proxy authentication

These settings allow you to require your applications to authenticate when using the WinPX proxy. This is useful when you run WinPX on a computer that is shared with other users, such as a Windows Terminal Server (WTS) aka Remote Desktop Services (RDS). As other users are on the same computer, they will be able to connect and use your WinPX proxy server without your knowledge. By requiring authentication, you can prevent other users from using your WinPX proxy server without your permission.

• Require local proxy authentication: Requires applications to authenticate when using the WinPX proxy.
• Secret: Provides the secret used for local proxy authentication. This secret is used in the WinPX proxy server URL, see the General tab for the URL with this option enabled.

Status Tab

Provides information about the current status of the WinPX proxy server, including:

• Proxy server status: Displays whether the WinPX proxy server is currently running or stopped.
• Current proxy configuration: Displays the current proxy configuration that WinPX is using.
• WinPX Proxy URL: The proxy URL to use in your Windows applications to connect to the WinPX proxy server.
• WSL Proxy URL: The proxy URL to use in WSL to connect to the WinPX proxy server. If WSL network mode is set to Mirrored, this URL will be the same as the WinPX Proxy URL. If WSL network mode is set to NAT, this URL will be different and will use the WSL2 network interface IP address.
• WSL Networking Mode: The current WSL2 networking mode, as determined by the WinPX proxy server. This can be either Mirrored, VirtioProxy, NAT, or None.

Diagnostics Tab

In this tab, you can check whether WinPX can access an URL through the configured proxy gateway. This is useful for troubleshooting network connectivity issues.

For instance, if you check the URL https://www.example.com/ and click Check URL, the following output may be generated:

Resolving proxy for 'https://www.example.com/'...
Resolved proxy: proxy.contoso.com:8080
Sending GET request to 'https://www.example.com/'...
HTTP status code: OK (200)
----------------------------------------
HTTP/1.1 200 OK
...

In the example above, WinPX was able to resolve the proxy for the URL https://www.example.com/ and successfully sent a GET request to the URL.

In the result view, you can see the response status line and the response HTTP headers. This information can help you diagnose any issues with your network connectivity or proxy configuration.

Note that problematic status codes typically start with 5xx. For instance, a 404 Not Found response is not an error related to WinPX, neither is a 301 Moved Permanently response. On the other hand, a 502 Bad Gateway response indicates that the WinPX proxy server was unable to reach the upstream proxy server, so you might want to check your proxy gateway configuration.