smtp timeout exception when trying to send

0 votes
asked Sep 6, 2013 by Eric1 (190 points)
edited Sep 9, 2013

Hi, I’m working on an automated email support system and I am having a lot of trouble with the class. The SmtpClient in .Net works fine but there doesn’t seem to be a way to convert the Rebex MailMessage to the

What seems to be happening is the smtp class gets a timeout exception after sending the message body. The messages I've tested with are simple text body and no attachments or resources. Its our corporate exchange server that does not require credentials, not using SSL.

Here's the code Private Sub SendMMessageRebex(ByVal oMsg As MailMessage) Dim _smtp As Smtp = Nothing Try _smtp = New Rebex.Net.Smtp() With _smtp .LogWriter = mTraceLogSMTPLogWriter If mServiceConfig.SMTPPort = 0 Then .Connect(mServiceConfig.SMTPHost, mServiceConfig.SMTPSSLMode) Else .Connect(mServiceConfig.SMTPHost, mServiceConfig.SMTPPort, mServiceConfig.SMTPSSLMode) End If If mServiceConfig.SMTPRequireLogin Then .Login(mServiceConfig.UserName, mServiceConfig.Password) End If .Send(oMsg) .Disconnect() End With Catch ex As Exception Fire_ReportStatus(Rebex.LogLevel.Error, "err, could not Send forwarded message, {0}", ex.ToString()) Finally If _smtp IsNot Nothing Then _smtp.Dispose() End If _smtp = Nothing End Try End Sub

here is the Log (edited my info with x's) Info: Connecting to using Smtp 2.0.4981.0. Info: Connection succeeded. Response: 220 Microsoft ESMTP MAIL Service, Version: 6.0.3790.4675 ready at Thu, 5 Sep 2013 16:28:00 -0400 Command: EHLO xxxxxxxx Response: Hello [] Response: 250-TURN Response: 250-SIZE Response: 250-ETRN Response: 250-PIPELINING Response: 250-DSN Response: 250-ENHANCEDSTATUSCODES Response: 250-8bitmime Response: 250-BINARYMIME Response: 250-CHUNKING Response: 250-VRFY Response: 250-X-EXPS GSSAPI NTLM LOGIN Response: 250-X-EXPS=LOGIN Response: 250-AUTH GSSAPI NTLM LOGIN Response: 250-AUTH=LOGIN Response: 250-X-LINK2STATE Response: 250-XEXCH50 Response: 250 OK Command: MAIL FROM:<xxxxxx> BODY=8BITMIME SIZE=287 Response: 250 2.1.0 xxxxxx....Sender OK Command: RCPT TO:<xxxxxx> NOTIFY=FAILURE Response: 250 2.1.5 xxxxxx Command: BDAT 287 LAST Info: Rebex.Net.SmtpException: Timeout exceeded. at Rebex.Net.Smtp.AL() at Rebex.Net.Smtp.NL(Int32 A, Boolean B) at Rebex.Net.Smtp.YBB(Boolean A, String[] B, VHB C, String D, Int64 E) at Rebex.Net.Smtp.ACB(String A, String[] B, String C, Stream D, TransferEncoding E) at Rebex.Net.Smtp.GCB(MimeMessage A, Stream B, MailAddress C, MailAddressCollection D) at Rebex.Net.Smtp.HCB(MimeMessage A, MailAddress B, MailAddressCollection C) Command: QUIT

Applies to: Rebex Secure Mail
commented Sep 9, 2013 by Tomas Knopp (58,890 points)
edited Sep 9, 2013

Thank you for your question, we will get back to you with an answer as soon as possible.

2 Answers

0 votes
answered Sep 9, 2013 by Tomas Knopp (58,890 points)
edited Sep 9, 2013
Best answer


please disable the Chunking and Pipelining extensions before sending the message. To do so, you can use the EnabledExtensions property of the Smtp class as in the example below:

Dim _smtp As Smtp = New Rebex.Net.Smtp()
' disable chunking and pipelining extension
_smtp.EnabledExtensions = SmtpExtensions.All And Not (SmtpExtensions.Chunking Or SmtpExtensions.Pipelining)

Please let us know if it has helped.

0 votes
answered Sep 9, 2013 by Eric1 (190 points)
edited Sep 9, 2013

That worked, thank you.