"Relay Denied" but no match for outlook!

[dp]

I am using the following code in .net 2:

MailAddress fromAddress = new MailAddress("va lid_smtp_addr", "name");
MailMessage message = new MailMessage();
message.From = fromAddress;
message.To.Add( new MailAddress("so *********@yahoo .com"));
message.Body = Body;
message.Subject = Subject;
message.IsBodyH tml = true;
SmtpClient smtp = new SmtpClient("val id_smtp_srv");

smtp.Credential s = new System.Net.Netw orkCredential
("valid_smtp_ad dr", "valid_pwd" );
smtp.Send(messa ge);

---

No errors (with the authentication to the smtp server etc etc) but still all
I get is the "Relay Denied" response.
Outlook express does manage to send the same email through the same smtp
server using the same settings, though !

How is this possible ? What's the difference between outlook and my code ?

thanx

[dp]

TIP:
According to the server log the outlook succeeds in authentication but the
c# code sends the wrong command and the smtp always responds with message
"SMTPS:S:50 4 Mechanism not supported".

Maybe this is a lead ?
How the authentication method can be configured in code ?

still, anyone on the original question ?
"dp" wrote:

I am using the following code in .net 2:

MailAddress fromAddress = new MailAddress("va lid_smtp_addr", "name");
MailMessage message = new MailMessage();
message.From = fromAddress;
message.To.Add( new MailAddress("so *********@yahoo .com"));
message.Body = Body;
message.Subject = Subject;
message.IsBodyH tml = true;
SmtpClient smtp = new SmtpClient("val id_smtp_srv");

smtp.Credential s = new System.Net.Netw orkCredential
("valid_smtp_ad dr", "valid_pwd" );
smtp.Send(messa ge);

---

No errors (with the authentication to the smtp server etc etc) but still all
I get is the "Relay Denied" response.
Outlook express does manage to send the same email through the same smtp
server using the same settings, though !

How is this possible ? What's the difference between outlook and my code ?

thanx

[Andreas Schubert]

hmm, really not sure if this is the right answer, but Outlook has a
mechanism to prevent sending mails through other applicatíons. However,
there is a registry switch to change this behaviour.

HTH

Andy

"dp" <dp@discussions .microsoft.com> schrieb im Newsbeitrag
news:AD******** *************** ***********@mic rosoft.com...

TIP:
According to the server log the outlook succeeds in authentication but the
c# code sends the wrong command and the smtp always responds with message
"SMTPS:S:50 4 Mechanism not supported".

Maybe this is a lead ?
How the authentication method can be configured in code ?

still, anyone on the original question ?
"dp" wrote:

I am using the following code in .net 2:

MailAddress fromAddress = new MailAddress("va lid_smtp_addr", "name");
MailMessage message = new MailMessage();
message.From = fromAddress;
message.To.Add( new MailAddress("so *********@yahoo .com"));
message.Body = Body;
message.Subject = Subject;
message.IsBodyH tml = true;
SmtpClient smtp = new SmtpClient("val id_smtp_srv");

smtp.Credential s = new System.Net.Netw orkCredential
("valid_smtp_ad dr", "valid_pwd" );
smtp.Send(messa ge);

---

No errors (with the authentication to the smtp server etc etc) but still
all
I get is the "Relay Denied" response.
Outlook express does manage to send the same email through the same smtp
server using the same settings, though !

How is this possible ? What's the difference between outlook and my code
?

thanx

[dp]

I strongly suspect authentication is not supported by
System.Net.Mail .SmtpClient at all.
The c# source code found at:
http://www.codeproject.com/csharp/EmailMessage.asp
does the whole smtp protocol communication manually and it works !
(btw, many many thanx to Peter Wone for his _working_ code)

I've tried it with all the same settings as in my original code and relay is
no longer an issue (since I am authenticated of course).

I still can't believe SmtpClient fails to send the AUTH LOGIN smtp command
properly. Anyone got any ideas ?

thanx

"Andreas Schubert" wrote:

hmm, really not sure if this is the right answer, but Outlook has a
mechanism to prevent sending mails through other applicatÃ*ons. However,
there is a registry switch to change this behaviour.

HTH

Andy

"dp" <dp@discussions .microsoft.com> schrieb im Newsbeitrag
news:AD******** *************** ***********@mic rosoft.com...

TIP:
According to the server log the outlook succeeds in authentication but the
c# code sends the wrong command and the smtp always responds with message
"SMTPS:S:50 4 Mechanism not supported".

Maybe this is a lead ?
How the authentication method can be configured in code ?

still, anyone on the original question ?
"dp" wrote:

I am using the following code in .net 2:

MailAddress fromAddress = new MailAddress("va lid_smtp_addr", "name");
MailMessage message = new MailMessage();
message.From = fromAddress;
message.To.Add( new MailAddress("so *********@yahoo .com"));
message.Body = Body;
message.Subject = Subject;
message.IsBodyH tml = true;
SmtpClient smtp = new SmtpClient("val id_smtp_srv");

smtp.Credential s = new System.Net.Netw orkCredential
("valid_smtp_ad dr", "valid_pwd" );
smtp.Send(messa ge);

---

No errors (with the authentication to the smtp server etc etc) but still
all
I get is the "Relay Denied" response.
Outlook express does manage to send the same email through the same smtp
server using the same settings, though !

How is this possible ? What's the difference between outlook and my code
?

thanx