How to use system wide proxy settings?

Question

I'd like the SFTP client to automatically use the system wide proxy settings (under Windows XP+). Is this possible?

Cheers, Christian

Answer 1

You can use the following GetDefaultProxy method to retrieve the system proxy settings.

The following system proxy types (which can be set in Internet Options/Connections/Lan Settings/Advanced) are supported:

• Secure (https) ~ corresponds to HTTP CONNECT proxies - Rebex.Net.ProxyType.HttpConnect
• Socks (version 4) ~ corresponds SOCKS 4A proxies - Rebex.Net.ProxyType.Socks4a

The other two options which can be set using system settings (FTP-only and HTTP-only proxies) are not suitable for other protocols.

var sftp = new Sftp();
sftp.Proxy = ProxyHelper.GetDefaultProxy();
//sftp.LogWriter = new ConsoleLogWriter(LogLevel.Info);
sftp.Connect("test.rebex.net", 22);
sftp.Login("demo", "password");

...

public static Proxy GetDefaultProxy()
{
    using (var registry = Microsoft.Win32.Registry.CurrentUser.OpenSubKey("Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings"))
    {
        if ((int)registry.GetValue("ProxyEnable") == 1)
        {
            var proxyServer = (string)registry.GetValue("ProxyServer");
            if (!string.IsNullOrEmpty(proxyServer))
            {
                var proxy = new Proxy();
                foreach (string entry in proxyServer.Split(new char[] { ';' }))
                {
                    int n;
                    string hostAndPort;
                    if ((n = entry.IndexOf('=')) == -1)
                    {
                        if (entry.StartsWith("http://", StringComparison.Ordinal))
                            hostAndPort = entry.Substring(7);
                        else
                            hostAndPort = entry;
                        proxy.ProxyType = ProxyType.HttpConnect;
                    }
                    else
                    {
                        hostAndPort = entry.Substring(n + 1);
                        string type = entry.Substring(0, n);
                        if (type == "socks")
                            proxy.ProxyType = ProxyType.Socks4a;
                        else if (type == "https")
                            proxy.ProxyType = ProxyType.HttpConnect;
                        else
                            continue;
                    }

                    n = hostAndPort.IndexOf(':');
                    if (n < 1)
                        throw new ApplicationException("Invalid proxy format: " + hostAndPort);

                    proxy.Host = hostAndPort.Substring(0, n);
                    int port;
                    if (!int.TryParse(hostAndPort.Substring(n + 1), out port))
                    {
                        throw new ApplicationException("Invalid proxy port: " + hostAndPort);
                    }
                    proxy.Port = port;
                }

                if (proxy.ProxyType == ProxyType.None)
                    throw new ApplicationException("None of the default proxies is supported.");

                var proxyOverride = (string)registry.GetValue("ProxyOverride");
                if (proxyOverride != null)
                {
                    var bypassList = new List<string>();
                    foreach (string host in proxyOverride.Split(';'))
                    {
                        if (host == "<local>")
                            proxy.BypassProxyOnLocal = true;
                        else
                            bypassList.Add(host);
                    }
                    proxy.BypassList = bypassList.ToArray();
                }

                return proxy;
            }
        }
    }

    return new Proxy();
}

Comments

Thanks for letting me know! I'll check this out.