c# - C#如何使用tcp连接发送电子邮件而无需身份验证

问题描述

我正在尝试使用 C# 中的 TCP 连接将电子邮件发送到 smtp 服务器（本例中为 google）。我得到的响应是需要身份验证。

5.5.1 需要验证。了解详情\n5.5.1 https://support.google.com/mail/?p=WantAuthError h66sm663716vke.21 - gsmtp

没有身份验证。我不知道要向其发送电子邮件的帐户的用户名和密码。

我能够找到的所有其他示例都使用预构建的 SMTP 服务器并构建邮件消息。

当有人需要重置密码或我需要发送系统消息或其他任何内容时，我只想能够向任何电子邮件帐户发送电子邮件。

这是我的代码：

TcpClient tcpclient = new TcpClient();
tcpclient.Connect("smtp.gmail.com", 465);

//not sure if I need port 465 or 587.
// implicit SSL is always used on SMTP port 465
System.Net.Security.SslStream sslstream = new System.Net.Security.SslStream(tcpclient.GetStream());
sslstream.AuthenticateAsClient("smtp.gmail.com");

writer = new StreamWriter(sslstream);
reader = new StreamReader(sslstream);

string replyText = string.Empty;
string[] capabilities = null;

// read the server's initial greeting
readResponse(220);

// identify myself and get the server's capabilities
if (sendCommand("EHLO myserver.com", ref replyText) == 250)
{
    // parse capabilities
        capabilities = replyText.Split(new Char[] { '\n' });
}
else
{
    // EHLO not supported, have to use HELO instead, but then
        // the server's capabilities are unknown...

    capabilities = new string[] { };

    sendCommand("HELO myserver.com", 250);
}

    // check for pipelining support... (OPTIONAL!!!)
        if (Array.IndexOf(capabilities, "PIPELINING") != -1)
        {
                // can pipeline...

                // send all commands first without reading responses in between
                writer.WriteLine("MAIL FROM:<" + "myserver@myserver.com" + ">");
                writer.WriteLine("RCPT TO:<" + "anyemail@gmail.com" + ">");
                writer.WriteLine("DATA");
                writer.Flush();

                // now read the responses...

                Exception e = null;

                // MAIL FROM
                int replyCode = readResponse(ref replyText);
                if (replyCode != 250)
                    e = new SmtpCmdFailedException(replyCode, replyText);

                // RCPT TO
                replyCode = readResponse(ref replyText);
                if ((replyCode != 250) && (replyCode != 251) && (e == null))
                    e = new SmtpCmdFailedException(replyCode, replyText);

                // DATA
                replyCode = readResponse(ref replyText);
                if (replyCode == 354)
                {
                    // DATA accepted, must send email followed by "."
                    writer.WriteLine("Subject: Email test");
                    writer.WriteLine("Test 1 2 3");
                    writer.WriteLine(".");
                    writer.Flush();

                    // read the response
                    replyCode = readResponse(ref replyText);
                    if ((replyCode != 250) && (e == null))
                        e = new SmtpCmdFailedException(replyCode, replyText);
                }
                else
                {
                    // DATA rejected, do not send email
                    if (e == null)
                        e = new SmtpCmdFailedException(replyCode, replyText);
                }

                if (e != null)
                {
                    // if any command failed, reset the session
                    sendCommand("RSET");
                    throw e;
                }
            }
            else
            {
                // not pipelining, MUST read each response before sending the next command...

                sendCommand("MAIL FROM:<" + "myserver@myserver.com" + ">", 250);
                try
                {
                    sendCommand("RCPT TO:<" + "anyemail@gmail.com" + ">", 250, 251);
                    sendCommand("DATA", 354);
                    writer.WriteLine("Subject: Email test");
                    writer.WriteLine("");
                    writer.WriteLine("Test 1 2 3");
                    writer.Flush();
                    sendCommand(".", 250);
                }
                catch (SmtpCmdFailedException e)
                {
                    // if any command failed, reset the session
                    sendCommand("RSET");
                    throw;
                }
            }

            // all done
            sendCommand("QUIT", 221);

标签： c#emailauthenticationtcpsmtp

c# - C#如何使用tcp连接发送电子邮件而无需身份验证

问题描述

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