使用TcpClient类连接到smtp.live.com [英] Connecting to smtp.live.com with the TcpClient class

问题描述

我正在尝试使用TcpClient类连接到smtp.live.com.这里有一个很棒的连接Gmail的示例:测试SMTP服务器是否通过C#运行

I'm trying to connect to smtp.live.com using the TcpClient class. There is a wonderful example of connecting to Gmail here: Testing SMTP server is running via C#

不幸的是，当更新它以与smtp.live.com一起使用时，调用AuthenticateAsClient方法时，我收到"IOException:握手由于意外的数据包格式而失败."

Unfortunately, when updating this to work with smtp.live.com, I'm getting an "IOException: The handshake failed due to an unexpected packet format" when the AuthenticateAsClient method is called.

我该如何解决?

class Program
{
    static void Main(string[] args)
    {
        using (var client = new TcpClient())
        {
            var server = "smtp.live.com";
            var port = 25;
            client.Connect(server, port);
            using (var stream = client.GetStream())
            using (var sslStream = new SslStream(stream))
            {
                // Getting an IOException here
                sslStream.AuthenticateAsClient(server);
                using (var writer = new StreamWriter(sslStream))
                using (var reader = new StreamReader(sslStream))
                {
                    writer.WriteLine("EHLO " + server);
                    writer.Flush();
                    Console.WriteLine(reader.ReadLine());
                }
            }
        }
        Console.WriteLine("Press Enter to exit...");
        Console.ReadLine();
    }
}

我尝试在AuthenticateAsClient中指定SslProtocol.Tls或Ssl3都不起作用.

I tried specifying the SslProtocol in AuthenticateAsClient. Neither Tls or Ssl3 worked.

还尝试提供RemoteCertificateValidation的回调，以防服务器证书无效时始终返回true.那也不起作用.

Also tried providing a callback for RemoteCertificateValidation that alway returned true just in case the server cert was invalid. That didn't work either.

注意:请不要建议我使用SmtpClient.我需要更多的控制权.

NOTE: Please do not suggest that I use SmtpClient; I need more control than it provides.

推荐答案

感谢您将我带入正确的轨道.smtp.live.com服务器需要以下事件序列:

Thanks to nos for putting me on the right track. The smtp.live.com servers require the following sequence of events:

1. 连接
2. HELO-在发送STARTTLS之前，它将不接受
3. STARTTLS-显然，这将服务器设置为接受加密连接
4. SslStream.AuthenticateAsClient()-这似乎使C#框架和SMTP服务器了解":)
5. 现在我们已经建立了加密连接，通常的SMTP命令就可以使用

无论如何，此代码对端口587上的smtp.live.com和smtp.gmail.com均有效:

Anyway, this code works for both smtp.live.com AND smtp.gmail.com on port 587:

class Program
{
    static void Main(string[] args)
    {
        const string server = "smtp.live.com";
        const int port = 587;
        using (var client = new TcpClient(server, port))
        {
            using (var stream = client.GetStream())
            using (var clearTextReader = new StreamReader(stream))
            using (var clearTextWriter = new StreamWriter(stream) { AutoFlush = true })
            using (var sslStream = new SslStream(stream))
            {
                var connectResponse = clearTextReader.ReadLine();
                if (!connectResponse.StartsWith("220"))
                    throw new InvalidOperationException("SMTP Server did not respond to connection request");

                clearTextWriter.WriteLine("HELO");
                var helloResponse = clearTextReader.ReadLine();
                if (!helloResponse.StartsWith("250"))
                    throw new InvalidOperationException("SMTP Server did not respond to HELO request");

                clearTextWriter.WriteLine("STARTTLS");
                var startTlsResponse = clearTextReader.ReadLine();
                if (!startTlsResponse.StartsWith("220"))
                    throw new InvalidOperationException("SMTP Server did not respond to STARTTLS request");

                sslStream.AuthenticateAsClient(server);

                using (var reader = new StreamReader(sslStream))
                using (var writer = new StreamWriter(sslStream) { AutoFlush = true })
                {
                    writer.WriteLine("EHLO " + server);
                    Console.WriteLine(reader.ReadLine());
                }
            }
        }
        Console.WriteLine("Press Enter to exit...");
        Console.ReadLine();
    }
}

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