Configure WinSCP .NET Proxy Settings with AddRawSettings

On an existing SessionOptions, select the proxy method as well as its endpoint. For HTTP CONNECT:

options.AddRawSettings("ProxyMethod", "3");
options.AddRawSettings("ProxyHost", "proxy.example");
options.AddRawSettings("ProxyPort", "8080");

options is the session configuration already containing the remote file-server host, port and account. Apply the proxy settings before opening that session through the application's existing lifecycle. For a publicly reachable SFTP server on a route that permits public intermediaries, choose a candidate from the HTTP proxy list for ProxyHost and ProxyPort. Keep ProxyUsername and ProxyPassword unset for an unauthenticated candidate and confirm that it permits the destination host and SSH port.

Method 3 identifies HTTP CONNECT in the documented method table; it is not port 3 or a universal proxy type. A SOCKS or FTP-gateway route needs its own supported method. The AddRawSettings reference links to the actual names and values.

Keep the intermediary account separate from the file-server account. When needed, ProxyUsername and ProxyPassword configure the proxy credentials. For SFTP, retain SSH host-key verification for the actual destination. For an FTPS session that logs in but cannot list files, check the separate data connection.

WinSCP can also generate a code template from a configured session. Review it against the documented method table instead of copying an unexplained numeric value. These session settings imply no change to the system's default web proxy.