System.Net.Mail.SmtpClient

G

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!
 
S

Sean Chambers

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
 
G

Guest

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?
 
S

Steven Cheng[MSFT]

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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