5.7.0用户未使用mailkit和strato服务器在asp.net core1中进行身份验证

Question

在asp.net core 1应用程序中,我正在尝试使用mailkit库(版本1.8.1)向strato服务器发送电子邮件.我的代码:

  var emailMessage = new MimeKit.MimeMessage();
  try
  {
      emailMessage.From.Add(new MimeKit.MailboxAddress("Support", "some@test.com"));
      emailMessage.To.Add(new MimeKit.MailboxAddress("", "test@test.com"));
      emailMessage.Subject = "Subject";
      var bodyBuilder = new MimeKit.BodyBuilder();
      bodyBuilder.HtmlBody = @"<b>Some body</b>";

      emailMessage.Body = bodyBuilder.ToMessageBody(); 

      using (var client = new MailKit.Net.Smtp.SmtpClient())
      {
          client.Timeout = 15000;
          // Accept all SSL certificates (in case the server supports STARTTLS)
          client.ServerCertificateValidationCallback = (s, c, h, e) => true;

          await client.ConnectAsync("smtp.strato.de", 587, MailKit.Security.SecureSocketOptions.Auto);
          // Note: since we don't have an OAuth2 token, disable
          // the XOAUTH2 authentication mechanism.
          client.AuthenticationMechanisms.Remove("XOAUTH2");

          // Note: only needed if the SMTP server requires authentication
          await client.AuthenticateAsync(login, passord);

          await client.SendAsync(emailMesage);//here error!
          await client.DisconnectAsync(true);
      }
      return true;
  }
  catch (System.Exception)
  {
      return false;
  } 

当我尝试发送电子邮件时 ,尽管身份验证通过,我仍然获得5.7.0 User not authenticated错误.例如,使用gmail的相同代码可以正常工作.

任何想法如何解决它？

Answer 1

问题是当SMTP客户端在身份验证后发送EHLO命令时,smtp.strato.de会重置其身份验证状态,即使规范强烈建议客户端应该这样做.

换句话说,smtp.strato.de已被破坏.

也就是说,您可以通过执行以下操作来解决此问题:

client.QueryCapabilitiesAfterAuthenticating = false;

只要在进行身份验证之前将该属性设置为false ,它就会起作用.