Как я могу отправлять электронные письма через SSL SMTP с помощью .NET Framework?

Question

Можно ли с помощью .NET Framework отправлять электронные письма через SMTP-сервер SSL через порт 465?

Обычный способ:

System.Net.Mail.SmtpClient _SmtpServer = new System.Net.Mail.SmtpClient("tempurl.org");
_SmtpServer.Port = 465;
_SmtpServer.EnableSsl = true;
_SmtpServer.Credentials = new System.Net.NetworkCredential("username", "password");
_SmtpServer.Timeout = 5000;
_SmtpServer.UseDefaultCredentials = false;

MailMessage mail = new MailMessage();
mail.From = new MailAddress(from);
mail.To.Add(to);
mail.CC.Add(cc);
mail.Subject = subject;
mail.Body = content;
mail.IsBodyHtml = useHtml;
_SmtpServer.Send(mail);

время ожидания:

System.Net Verbose: 0 : [1024] SmtpClient::.ctor(host=ssl0.ovh.net, port=465)
System.Net Information: 0 : [1024] Associating SmtpClient#64923656 with SmtpTransport#44624228
System.Net Verbose: 0 : [1024] Exiting SmtpClient::.ctor()  -> SmtpClient#64923656
System.Net Information: 0 : [1024] Associating MailMessage#17654054 with Message#52727599
System.Net Verbose: 0 : [1024] SmtpClient#64923656::Send(MailMessage#17654054)
System.Net Information: 0 : [1024] SmtpClient#64923656::Send(DeliveryMethod=Network)
System.Net Information: 0 : [1024] Associating SmtpClient#64923656 with MailMessage#17654054
System.Net Information: 0 : [1024] Associating SmtpTransport#44624228 with SmtpConnection#14347911
System.Net Information: 0 : [1024] Associating SmtpConnection#14347911 with ServicePoint#51393439
System.Net.Sockets Verbose: 0 : [1024] Socket#26756241::Socket(InterNetwork#2)
System.Net.Sockets Verbose: 0 : [1024] Exiting Socket#26756241::Socket() 
System.Net.Sockets Verbose: 0 : [1024] Socket#23264094::Socket(InterNetworkV6#23)
System.Net.Sockets Verbose: 0 : [1024] Exiting Socket#23264094::Socket() 
System.Net.Sockets Verbose: 0 : [1024] Socket#26756241::Connect(20:465#337754884)
System.Net.Sockets Verbose: 0 : [1024] Exiting Socket#26756241::Connect() 
System.Net.Sockets Verbose: 0 : [1024] Socket#23264094::Close()
System.Net.Sockets Verbose: 0 : [1024] Socket#23264094::Dispose()
System.Net.Sockets Verbose: 0 : [1024] Exiting Socket#23264094::Close() 
System.Net Information: 0 : [1024] Associating SmtpConnection#14347911 with SmtpPooledStream#14303791
System.Net.Sockets Verbose: 0 : [1024] Socket#26756241::Receive()
System.Net.Sockets Verbose: 0 : [2404] Socket#26756241::Dispose()
System.Net.Sockets Error: 0 : [1024] Exception in the Socket#26756241::Receive - A blocking operation was interrupted by a call to WSACancelBlockingCall
System.Net.Sockets Verbose: 0 : [1024] Exiting Socket#26756241::Receive()   -> 0#0
System.Net Error: 0 : [1024] Exception in the SmtpClient#64923656::Send - Unable to read data from the transport connection: A blocking operation was interrupted by a call to WSACancelBlockingCall.
System.Net Error: 0 : [1024]    at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
   at System.Net.DelegatedStream.Read(Byte[] buffer, Int32 offset, Int32 count)
   at System.Net.BufferedReadStream.Read(Byte[] buffer, Int32 offset, Int32 count)
   at System.Net.Mail.SmtpReplyReaderFactory.ReadLines(SmtpReplyReader caller, Boolean oneLine)
   at System.Net.Mail.SmtpReplyReaderFactory.ReadLine(SmtpReplyReader caller)
   at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port)
   at System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port)
   at System.Net.Mail.SmtpClient.GetConnection()
   at System.Net.Mail.SmtpClient.Send(MailMessage message)
System.Net Verbose: 0 : [1024] Exiting SmtpClient#64923656::Send() 
System.Net Information: 0 : [1024] Associating MailMessage#49584532 with Message#19699911

Я погуглил и обнаружил, что System.Net.Mail поддерживает соединения через порт 587 (порт по умолчанию для явного SSL, который начинается незашифрованным, затем выдает STARTDLS, затем переключается на зашифрованное соединение: RFC 2228), но не поддерживает неявный SSL (все соединение обернуто в слой SSL) ...

Answer 1

Если есть сомнения в этом коде, пожалуйста, задавайте свои вопросы (здесь для gmail номер порта 587)

// code to Send Mail 
// Add following Lines in your web.config file 
//               <system.net>
//                  <mailSettings>
//                    <smtp>
//                        <network host="smtp.gmail.com" port="587" userName="xxx@gmail.com" password="yyy"   defaultCredentials="false"/>
//                    </smtp>
//               </mailSettings>
//               </system.net>
// Add below lines in your config file inside appsetting tag <appsetting></appsetting>
//          <add key="emailFromAddress" value="xxxx@gmail.com"/>
//       <add key="emailToAddress" value="xxxxxxx@gmail.com"/>
//        <add key="EmailSsl" value="true"/>

// Namespace Used

using System.Net.Mail;
     public static bool SendingMail(string subject, string content)
    {
       // getting the values from config file through c#
        string fromEmail = ConfigurationSettings.AppSettings["emailFromAddress"];
        string mailid = ConfigurationSettings.AppSettings["emailToAddress"];
        bool useSSL;
        if (ConfigurationSettings.AppSettings["EmailSsl"] == "true")
        {
            useSSL = true;
        }
        else
        {
            useSSL = false;
        }



        SmtpClient emailClient;
        MailMessage message;
        message = new MailMessage();
        message.From = new MailAddress(fromEmail);
        message.ReplyTo = new MailAddress(fromEmail);
        if (SetMailAddressCollection(message.To, mailid))
        {
            message.Subject = subject;
            message.Body = content;
            message.IsBodyHtml = true;
            emailClient = new SmtpClient();
            emailClient.EnableSsl = useSSL;
            emailClient.Send(message);
        }
        return true;
    }
    // if you are sending mail in group

    private static bool SetMailAddressCollection(MailAddressCollection toAddresses, string    mailId)
    {
        bool successfulAddressCreation = true;
        toAddresses.Add(new MailAddress(mailId));
        return successfulAddressCreation;
    }