发送电子邮件：对等方重置连接

Question

假设我有一个像下面这样的函数，可以完美地从套接字发送和接收信息..

结果是：

Connected to: 65.55.96.11 Port: 25
220 BLU0-SMTP374.blu0.hotmail.com Microsoft ESMTP MAIL Service, Version: 6.0.3790.4675 ready at  Mon, 31 Dec 2012 19:52:22 -0800 

250 BLU0-SMTP374.blu0.hotmail.com Hello [50.100.44.155]

220 2.0.0 SMTP server ready

Exception: Socket Error 10054: Connection reset by peer

为什么会出现异常？当我发送“DATA”字符串时它会抛出异常。

如何登录？我似乎无法在网上找到任何地方。我搜索了它，只看到 AUTH 命令，但根本没有用法或示例。

代码如下：

void SendEmail(std::string Username, std::string Password, std::string IP, std::string Port)
{
  Socket = CreateSocket;
  ConnectSocket(Socket, IP, Port);
  SetTimeout(Socket, 10000);
  SocketInfo(Socket, IP, Port);

  writeln("Connected to: " + IP + " Port: " + Port);
  writeln(RecvSocket(Socket));

  SendSocketEx(Socket, "HELO");    //SendSocketEx automatically adds \r\n to the end of a line..
  writeln(RecvSocket(Socket));

  SendSocketEx(Socket, "STARTTLS");
  writeln(RecvSocket(Socket));

  SendSocketEx(Socket, "MAIL FROM: mehwtfbleh@hotmail.com");
  writeln(RecvSocket(Socket));

  SendSocketEx(Socket, "VRFY mehwtfbleh@hotmail.com");
  writeln(RecvSocket(Socket));

  SendSocketEx(Socket, "RCPT TO: mehwtfbleh@hotmail.com");
  writeln(RecvSocket(Socket));

  SendSocketEx(Socket, "DATA");
  writeln(RecvSocket(Socket));

  SendSocketEx(Socket, "This Is The Body..");
  writeln(RecvSocket(Socket));

  SendSocketEx(Socket, "QUIT");
  writeln(RecvSocket(Socket));

  CloseSocket(Socket);
  FreeSocket(Socket);
}

int main()
{
    SendEmail("", "", "smtp.live.com", "25", "localhost");
}

Answer 1

问题是该服务器需要通过 TLS 协议进行通信。的STARTTLS命令告诉所有进一步的通信将发生在安全套接字层（SSL / TLS）服务器。一旦建立此连接，双方之间的所有进一步通信都将被加密。

实现这一点的最简单方法是使用实现 SSL/TLS的库。最著名的库是 OpenSSL。

您可以从终端/控制台使用 OpenSSL 执行快速测试：

openssl s_client -connect smtp.live.com:25 -starttls smtp -crlf

然后你可以发送你的命令：

EHLO hotmail.com
AUTH LOGIN (this depends on the methods supported by the server)
...
MAIL FROM: <your email>
RCPT TO: <recipient email>
DATA
All your SMTP are belong to us.
.