SmtpClient - 无法循环发送电子邮件 [英] SmtpClient - unable to send email in a loop

问题描述

您好，

我使用的是System.Net.Mail.SmtpClient发送电子邮件。

在一个循环中，我正在调用一个以一分钟的时间间隔发送电子邮件的函数。

功能流程： -

创建SmtpClient即客户端。

设置client.ServicePoint.maxIdleTime = 0;

client.ServicePoint.ConnectionLeaseTimeout = 0;

groupName = client.ServicePoint.ConnectionName ;

表单MailMessage

client.Send（MailMessage）

关闭客户端 - client.ServicePoint.CloseConnectionGroup （groupName）

并设置client = null;

发送第一封电子邮件正确。

当调用SmtpClient.Send发送第二封电子邮件时 - 它会抛出异常。

SmtpException-发送电子邮件失败。

StatusCode - GeneralFailure。

InnerException - 无法从tran读取数据运动连接：net_io_connectionclosed。

如果我将发送电子邮件的时间间隔从一分钟增加到两分钟，程序可以正常工作正确。

我的理解是我通过调用CloseConnectionGroup和

$ b $强制SMtpClient关闭与服务器的连接b

设置ConnectionLeaseTimeout = 0.

如果我使用netstat实用程序检查网络连接，则显示与SMTP服务器的连接处于CLOSE_WAIT状态且未被删除直到服务器的连接超时到期，即60秒。

此外，每次我创建新的连接以发送电子邮件时，为什么我不能只打开一个新连接并让旧的连接超时。

任何人都可以解释为什么我不能以一分钟的间隔发送电子邮件吗？

FYI：这是一个控制台应用程序。

谢谢，

问候，

Aparna

解决方案

您好Aparna，

您有没有找到解决方案？我有相同的问题循环通过电子邮件。前1个没问题，之后就失败了。感谢。搜索结果，搜索添

Hi ,

 

I am using System.Net.Mail.SmtpClient to send email.

 

In a loop I am calling a function that sends email at one minute time interval.

 

The flow of function:-

Create SmtpClient i.e. client.

Set client.ServicePoint.maxIdleTime = 0;

client.ServicePoint.ConnectionLeaseTimeout = 0;

groupName = client.ServicePoint.ConnectionName;

Form MailMessage

client.Send( MailMessage)

Close client - client.ServicePoint.CloseConnectionGroup(groupName)

and set client = null;

 

The first email is send properly.

When SmtpClient.Send is called for sending second email - it throws Exception.

SmtpException- Failure sending email.

StatusCode - GeneralFailure.

InnerException - Unable to read data from transport connection:net_io_connectionclosed.

 

If I increase the time interval at which I send email from one minute to two minute the program works properly.

 

My understanding is I am forcing SMtpClient to close connection with server by calling CloseConnectionGroup and

setting ConnectionLeaseTimeout = 0.

If I use netstat utility to check network connection it shows the connection to SMTP Server goes in CLOSE_WAIT state and is not dropped until Server's connection timeout expires i.e 60 seconds.

Moreover, everytime I am creating a new connection to send email, so why cannot I just open a new connection and let the old connection timeout.

 

Can anyone explain why I am not able to send email at one minute interval?

 

FYI: This is a console application.

 

Thanks,

Regards,

Aparna

 

 

解决方案

Hi Aparna,

Did you ever figure out a solution to this?  I have the same issue looping through e-mails.  First 1 goes fine, after that it fails.  Thanks.

Tim

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