Perhaps this is more of an IIS question than programming, but I’ll throw it out there nonetheless.
I am attempting to send an email via SMTP with C# using the following test code:
//params: from email, to email, subject, body
MailMessage m = new MailMessage( <sendemail>, <receiveemail>, "testsubject", "Testbody" );
SmtpClient c = new SmtpClient( <SMTP Server> );
c.Send( m );
Extremely simple. I am avoiding credentials entirely because of the configuration on my SMTP server:
alt text http://img683.imageshack.us/img683/8909/smtp1.png
This should allow me to connect without credentials. Alternatively I’ve tried empty strings for username/password, and default credentials.
When I send attempt to send, I get the “Sending SMTP Email to failed with the following error: Mailbox unavailable. The server response was: 5.7.1 Unable to relay for ” Error. I go to the relay section of IIS, and it is as follows:
alt text http://img192.imageshack.us/img192/5002/smtp2.png
So my thought is even though the “Allow all computers which successfully authenticate to relay” option is enabled, since I allow anonymous authentication my application is not able to relay. Is this the case? If so, how do I go about fixing my code to be able to relay? I’ve tried messages to emails inside and outside of the domain, to no avail. This is a server 2003 machine.
Your assessment is correct.
You can either switch to using authenticated connections, or else add all of the IP’s/Domains that your code will run from to the relay exceptions list.