System.Net.Mail.SmtpClient

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Guest

Hi all,

We are using the Asp.Net SMTP Client to send email via our Exchange 2003 SP2
Server. When trying to send email to a local recipient I am getting the
following error:-

Server: 172.19.2.21. Message: Mailbox unavailable. The server response was:
5.7.1 Requested action not taken: message refused


What is causing this? The asp.net machine is on the same LAN as the Exchange
Server. I checked the Exchange Server and all local IPs are in the "allow"
list.

TIA!
 
How do you have the Recipient MailAddress setup? Are you using
(e-mail address removed) or (e-mail address removed)

Sounds like an issue with formatting the address correctly, and now
with SmtpClient
 
For the recipient mailaddress I am using (e-mail address removed)

If I change the SMTPServer on the SMTPClient to another smtp server,
everything works fine.

What could be causing this?
 
Hello Param,

As for the send mail code, are you using the "Network" as the SmtpClient's
"SmtpDeliveryMethod" and have you tried supply a credential or use the
default credential. Also, when using Exchange server in a domain
environment, you should make sure you have permission to send mail as the
"From" address since exchange server will validate this at server-side.

In addition, as you mentioned it works when using another SMTP server, is
that SMTP server a normal SMTP relay server which also transfer message to
another exchange server? If possible you can also create a local
smtpserver through IIS which act as a relay server to the Exchange server
and send mail through this local SMTP server to see whether it works.

So far based on my experience, it is likely a server environment specific
issue. Here is a simple code snippet which works for sending mail to local
domain user through local network exchange server:

==========================
private void btnSend_Click(object sender, EventArgs e)
{
MailMessage msg = new
MailMessage("(e-mail address removed)","(e-mail address removed)");
msg.Subject = "Smtp Client Test Message";
msg.IsBodyHtml = true;
msg.Body = "<font size='30'>Hello World</font>";

SmtpClient sc = new SmtpClient("smtphost");

sc.DeliveryMethod = SmtpDeliveryMethod.Network;

sc.UseDefaultCredentials = true;

sc.Send(msg);

}
===========================

Please feel free to post here if you have any other finding or any other
questions on this.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead



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