我的问题可能是重复的问题，但我没有找到解决问题的正确方法。这就是我要问的原因。
我有一个asp网站。我正在使用smtpclient发送消息。我的代码在gmail设置下工作正常。但是在生产服务器中他们使用的是Bellnetwork的（smtp10.on.aibn.com）邮件服务器。他们正在使用端口25，也没有使用SSL（电子邮件提供商不支持SSL）。但是相同的邮件设置在过去的2 - 3年内运行正常，但现在当我们从我们的网站发送一些消息（生产）1或2时失败发送出去，其他人会成功发出。奇怪的是，过去3年没有问题。我收到了失败邮件的以下错误。
例外：
1
System.IO.IOException: Unable to read data from the transport connection: net_io_connectionclosed. at System.Net.Mail.SmtpReplyReaderFactory.ProcessRead(Byte[] buffer, Int32 offset, Int32 read, Boolean readLine) at System.Net.Mail.SmtpReplyReaderFactory.ReadLines(SmtpReplyReader caller, Boolean oneLine) at System.Net.Mail.SmtpReplyReaderFactory.ReadLine(SmtpReplyReader caller) at System.Net.Mail.CheckCommand.Send(SmtpConnection conn, String& response) at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, SmtpFailedRecipientException& exception) at System.Net.Mail.SmtpClient.Send(MailMessage message) --- End of inner exception stack trace --- at System.Net.Mail.SmtpClient.Send(MailMessage message) at Handler.BLL.cSendMail.SendMail(String p_strFrom, String p_strDisplayName, String p_strTo, String p_strSubject, String p_strMessage, String strFileName)
2
System.IO.IOException: Unable to read data from the transport connection: net_io_connectionclosed.
3
A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 67.69.240.69:25 System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 67.69.240.69:25 at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress) at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Int32 timeout, Exception& exception) --- End of inner exception stack trace --- at System.Net.ServicePoint.GetConnection(PooledStream PooledStream, Object owner, Boolean async, IPAddress& address, Socket& abortSocket, Socket& abortSocket6, Int32 timeout) at System.Net.PooledStream.Activate(Object owningObject, Boolean async, Int32 timeout, GeneralAsyncDelegate asyncCallback) at System.Net.PooledStream.Activate(Object owningObject, GeneralAsyncDelegate asyncCallback) at System.Net.ConnectionPool.GetConnection(Object owningObject, GeneralAsyncDelegate asyncCallback, Int32 creationTimeout) 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 Handler.BLL.cSendMail.SendMail(String p_strFrom, String p_strDisplayName, String p_strTo, String p_strSubject, String p_strMessage, String strFileName)
我的代码：
public bool SendMail(string p_strFrom, string p_strDisplayName, string p_strTo, string p_strSubject, string p_strMessage , string strFileName)
{
try
{
p_strDisplayName = _DisplayName;
string smtpserver = _SmtpServer;
SmtpClient smtpClient = new SmtpClient();
MailMessage message = new MailMessage();
MailAddress fromAddress = new MailAddress(_From,_DisplayName);
smtpClient.Host = _SmtpServer;
smtpClient.Port = Convert.ToInt32(_Port);
string strAuth_UserName = _UserName;
string strAuth_Password = _Password;
if (strAuth_UserName != null)
{
System.Net.NetworkCredential SMTPUserInfo = new System.Net.NetworkCredential(strAuth_UserName, strAuth_Password);
smtpClient.UseDefaultCredentials = false;
if (_SSL)
{
smtpClient.EnableSsl = true;
}
smtpClient.Credentials = SMTPUserInfo;
}
message.From = fromAddress;
message.Subject = p_strSubject;
message.IsBodyHtml = true;
message.Body = p_strMessage;
message.To.Add(p_strTo);
try
{
smtpClient.Send(message);
return true;
}
catch (SmtpException ee)
{
Log.WriteSpecialLog("smtpClient mail sending first try failed : " + ee.ToString(),"");
Log.WriteSpecialLog("status code : " + ee.StatusCode, "");
}
}
答案 0 :(得分：0)
此代码对我有用
public static string sendMail(string fromEmail, string toEmail, string subject, string body, string Name, string bcc="" , string replyTo="")
{
MailMessage mailer = new MailMessage
{
IsBodyHtml = true,
From = new MailAddress(fromEmail, "yoursite.com"),
Subject = subject,
Body = body,
BodyEncoding = Encoding.GetEncoding("utf-8")
};
mailer.To.Add(new MailAddress(toEmail, toEmail));
//
if (!string.IsNullOrEmpty(bcc))
{
mailer.Bcc.Add(bcc);
}
//
if (!string.IsNullOrEmpty(replyTo))
{
mailer.Headers.Add("Reply-To", replyTo);
}
//
AlternateView plainView = AlternateView.CreateAlternateViewFromString(Regex.Replace(body, "<(.|\\n)*?>", string.Empty), null, "text/plain");
AlternateView htmlView = AlternateView.CreateAlternateViewFromString(body, null, "text/html");
mailer.AlternateViews.Add(plainView);
mailer.AlternateViews.Add(htmlView);
SmtpClient smtp = new SmtpClient(ConfigurationManager.AppSettings["SMTPserver"]);
smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
//smtp.DeliveryMethod = SmtpDeliveryMethod.PickupDirectoryFromIis;
NetworkCredential basicAuthenticationInfo = new NetworkCredential(ConfigurationManager.AppSettings["passMail"], ConfigurationManager.AppSettings["passKey"]);
smtp.UseDefaultCredentials = false;
smtp.Credentials = basicAuthenticationInfo;
smtp.EnableSsl = false;
smtp.Port = ConfigurationManager.AppSettings["Port"];
//
try
{
smtp.Send(mailer);
return "Email sent successfully !";
}
catch (Exception ex)
{
return "Failure in Email Message= !" + ex.message;
}
}