Amazon SES 停止工作

我设置了 Amazon SES，它最初运行了几个小时，然后突然停止了。我发送的所有电子邮件以及我们的域都已经过验证。我们不会发送大量电子邮件 - 每天只发送几百封。每当我对 web.config 进行更改时，它似乎又可以再工作 2-3 小时。例如，它停止工作，所以我将端口 587 切换到 25，它开始工作 2-3 小时，然后停止。然后我又换回587，同样的事情发生了。一旦它停止工作，它似乎就不会自行重新启动。它运行在两台负载平衡服务器、asp.net Framework v2.0、IIS 7.5 上。这是我正在使用的代码：

网络配置：

<system.net>
  <mailSettings>
    <smtp deliveryMethod="Network" from="[email protected] /cdn-cgi/l/email-protection">
      <network defaultCredentials="false" host="email-smtp.us-east-1.amazonaws.com" userName="***" password="***" port="587" />
    </smtp>
  </mailSettings>
</system.net>

c# code:

var smtpClient = new SmtpClient() { EnableSsl = true };

var mailMessage =
    new MailMessage(fromAddress, toAddress, subject, body)
    {
        IsBodyHtml = true
    };

smtpClient.Send(mailMessage);

这是我收到的两个错误：

The following exception was thrown by the web event provider '(null)' in the application '/' (in an application lifetime a maximum of one exception will be logged per provider instance):

System.Web.HttpException: Unable to send out an e-mail to the SMTP server. Please ensure that the server specified in the <smtpMail> section is valid. ---> System.Net.Mail.SmtpException: Failure sending mail. ---> System.IO.IOException: Received an unexpected EOF or 0 bytes from the transport stream.
   at System.Net.FixedSizeReader.ReadPacket(Byte[] buffer, Int32 offset, Int32 count)
   at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
   at System.Threading.ExecutionContext.runTryCode(Object userData)
   at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Net.TlsStream.ProcessAuthentication(LazyAsyncResult result)
   at System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size)
   at System.Net.PooledStream.Write(Byte[] buffer, Int32 offset, Int32 size)
   at System.Net.Mail.SmtpConnection.Flush()
   at System.Net.Mail.ReadLinesCommand.Send(SmtpConnection conn)
   at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port)
   at System.Net.Mail.SmtpClient.Send(MailMessage message)
   --- End of inner exception stack trace ---
   at System.Net.Mail.SmtpClient.Send(MailMessage message)
   at System.Web.Management.MailWebEventProvider.SendMail(MailMessage msg)
   --- End of inner exception stack trace ---
   at System.Web.Management.MailWebEventProvider.SendMail(MailMessage msg)
   at System.Web.Management.SimpleMailWebEventProvider.SendMessageInternal(WebBaseEventCollection events, Int32 notificationSequence, Int32 begin, DateTime lastFlush, Int32 discardedSinceLastFlush, Int32 eventsInBuffer, Int32 messageSequence, Int32 messagesInNotification, Int32 eventsInNotification, Int32 eventsLostDueToMessageLimit)
   at System.Web.Management.SimpleMailWebEventProvider.SendMessage(WebBaseEvent eventRaised)
   at *****.Global.SimpleMailWithSslWebEventProvider.ProcessEvent(WebBaseEvent raisedEvent)
   at System.Web.Management.WebBaseEvent.RaiseInternal(WebBaseEvent eventRaised, ArrayList firingRuleInfos, Int32 index0, Int32 index1)

The following exception was thrown by the web event provider '(null)' in the application '/' (in an application lifetime a maximum of one exception will be logged per provider instance):

System.Web.HttpException: Unable to send out an e-mail to the SMTP server. Please ensure that the server specified in the <smtpMail> section is valid. ---> System.Net.Mail.SmtpException: Service not available, closing transmission channel. The server response was: Timeout waiting for data from client.
   at System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response)
   at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, SmtpFailedRecipientException& exception)
   at System.Net.Mail.SmtpClient.Send(MailMessage message)
   at System.Web.Management.MailWebEventProvider.SendMail(MailMessage msg)
   --- End of inner exception stack trace ---
   at System.Web.Management.MailWebEventProvider.SendMail(MailMessage msg)
   at System.Web.Management.SimpleMailWebEventProvider.SendMessageInternal(WebBaseEventCollection events, Int32 notificationSequence, Int32 begin, DateTime lastFlush, Int32 discardedSinceLastFlush, Int32 eventsInBuffer, Int32 messageSequence, Int32 messagesInNotification, Int32 eventsInNotification, Int32 eventsLostDueToMessageLimit)
   at System.Web.Management.SimpleMailWebEventProvider.SendMessage(WebBaseEvent eventRaised)
   at *****.Global.SimpleMailWithSslWebEventProvider.ProcessEvent(WebBaseEvent raisedEvent)
   at System.Web.Management.WebBaseEvent.RaiseInternal(WebBaseEvent eventRaised, ArrayList firingRuleInfos, Int32 index0, Int32 index1)

我尝试在亚马逊论坛上寻求帮助，但没有成功。似乎有什么东西干扰了连接，但我不知道是什么。有任何想法吗？谢谢。

这听起来确实是一个棘手的问题 - 我对此并不是 100% 肯定，但您似乎错过了处置 SMTP 客户端，这在更改为VPC实例后发送电子邮件经常很慢 https://serverfault.com/q/452462/10305导致您看到的错误：

当我不处理 SmtpClient 时，我收到错误...

'服务不可用，正在关闭传输通道。服务器 响应是：等待来自客户端的数据超时。

这实际上可以很好地解释间歇性问题，即根据执行的代码路径，此问题可能会触发 SMTP 连接亚马逊SES http://aws.amazon.com/ses/挂起，这显然可以通过切换到另一个端口来解决，这意味着连接正在重置 - 这就是SmtpClient.Dispose 方法 http://msdn.microsoft.com/en-us/library/ee706941.aspx还确保：

向 SMTP 服务器发送 QUIT 消息，优雅地结束 TCP 连接，并释放当前实例使用的所有资源 这SMTP客户端 http://msdn.microsoft.com/en-us/library/system.net.mail.smtpclient.aspx class.

因此，适当的模式是促进使用语句 http://msdn.microsoft.com/en-us/library/yh598w02.aspx，如所示Amazon SES 和 .NET 入门 http://sesblog.amazon.com/post/Tx19TAGZFKPEPGP/Getting-Started-with-Amazon-SES-and-NET:

  String username = "SMTP-USERNAME";  // Replace with your SMTP username.
  String password = "SMTP-PASSWORD";  // Replace with your SMTP password.
  String host = "email-smtp.us-east-1.amazonaws.com";
  int port = 25;

  using (var client = new System.Net.Mail.SmtpClient(host, port))
  {
    client.Credentials = new System.Net.NetworkCredential(username, password);
    client.EnableSsl = true;

    client.Send
    (
              "[email protected] /cdn-cgi/l/email-protection",  // Replace with the sender address.
              "[email protected] /cdn-cgi/l/email-protection",    // Replace with the recipient address.
              "Testing Amazon SES through SMTP",              
              "This email was delivered through Amazon SES via the SMTP end point."
    );
  }

请注意，该示例使用端口 25，由于通常隐含发送限制，我强烈建议避免使用该端口，请参阅Addendum有关相应 Amazon EC2 限制的详细信息，请参见下文。

祝你好运！

Addendum

Amazon EC2 在端口 25 上进行限制

您可能知道这一点（实际上我认为这不是问题），但是亚马逊EC2 http://aws.amazon.com/ec2/ 对通过端口 25 发送的电子邮件施加默认发送限制，并在您尝试超出这些限制时限制出站连接使用时仍然适用亚马逊SES http://aws.amazon.com/ses/, see Amazon SES SMTP 问题 http://docs.aws.amazon.com/ses/latest/DeveloperGuide/smtp-issues.html:

您正在通过端口 25 从 Amazon EC2 实例发送到 Amazon SES 并且您无法达到 Amazon SES 发送限制或者您 接收超时— Amazon SES EC2 对以下内容施加默认发送限制 通过端口 25 发送的电子邮件并限制出站连接，如果您 尝试超越这些限制。要消除这些限制，请提交请求删除电子邮件发送限制 https://aws-portal.amazon.com/gp/aws/html-forms-controller/contactus/ec2-email-limit-rdns-request。您还可以连接到 Amazon SES 通过端口 465 或端口 587，这两个端口均不受限制。

因此，我会从您的测试/切换场景中删除端口 25，并仅使用端口 465/587，以避免错误引导（正如所引用的，您也可以请求删除此限制，但这需要几个小时，并且端口 25 似乎最好首先避免） - 有点不幸的是，几个官方 Amazon SES 示例正在使用端口 25，甚至没有提到这个容易触发的问题。