Sending Emails with port 465

Cooler · March 1st, 2011, 11:18 AM

If you are having issues with sending emails with port 465 like I am see the attached link.

http://blogs.msdn.com/b/webdav_101/a...-port-465.aspx

No fix applied in .net 4.0......

Sending mail using System.Net.Mail with SSL will fail:

System.Net.NetworkCredential aCred = new System.Net.NetworkCredential("myacct", "mypassword");
SmtpClient smtp = new SmtpClient("smtp.mail.myserver.com", 465);
smtp.EnableSsl = true;
smtp.UseDefaultCredentials = false;
smtp.Credentials = aCred;

System.Net.Mail only supports “Explicit SSL”.

Explicit SSL
System.Net.Mail only supports “Explicit SSL”. Explicit SSL starts as unencrypted on port 25, then issues a STARTTLS and switches to an Encrypted connection. See RFC 2228.

Explicit SLL would go something like: Connect on 25 -> StartTLS (starts to encrypt) -> authenticate -> send data

If the SMTP server expects SSL/TLS connection right from the start then this will not work.

If you see "530 Must issue a STARTTLS command first" being returned while trying to send a message, then Explicit SSL is what is being expected.

Implicit SSL
There is no way to use Implicit SSL (SMTPS) with System.Net.Mail. Implicit SSL would have the entire connection is wrapped in an SSL layer. A specific port would be used (port 465 is common). There is no formal RFC covering Implicit SSL.

Implicit SLL would go something like: Start SSL (start encryption) -> Connect -> Authenticate -> send data

This is not considered a bug, it’s by design. There are two types of SSL authentication for SMTP, and we only support one with System.Net.Mail (by design) – Explicit SSL.

Windows Mail uses System.Net.Mail to send messages - so it wont work with Implicit SSL. Outlook Express and System.Web.Mail use CDOSYS for sending messages and should work since CDOSYS can work with Explict SSL and Implicit SSL.

Cooler · March 1st, 2011, 11:51 AM

Solution:

ADD COM reference "Microsoft CDO for Windows 200 Library" to project

Tried it and though it does work not sure of implications.
IMAR are you aware of this work around and issues?

Code:

protected void Page_Load(object sender, EventArgs e)
    {
        string yourEmail = "name@provider";
 
        CDO.Message message = new CDO.Message(); 
        CDO.IConfiguration configuration = message.Configuration; 
        ADODB.Fields fields = configuration.Fields;
        ADODB.Field field = fields["http://schemas.microsoft.com/cdo/configuration/smtpserver"]; 
        field.Value = "smtp.provider"; 
        field = fields["http://schemas.microsoft.com/cdo/configuration/smtpserverport"]; 
        field.Value = 465; 
        field = fields["http://schemas.microsoft.com/cdo/configuration/sendusing"]; 
        field.Value = CDO.CdoSendUsing.cdoSendUsingPort; 
        field = fields["http://schemas.microsoft.com/cdo/configuration/smtpauthenticate"]; 
        field.Value = CDO.CdoProtocolsAuthentication.cdoBasic; 
        field = fields["http://schemas.microsoft.com/cdo/configuration/sendusername"]; 
        field.Value = yourEmail; 
        field = fields["http://schemas.microsoft.com/cdo/configuration/sendpassword"]; 
        field.Value = "password"; 
        field = fields["http://schemas.microsoft.com/cdo/configuration/smtpusessl"]; 
        field.Value = "true"; 
        fields.Update();

        message.From = yourEmail; 
        message.To = yourEmail; 
        message.Subject = "Test message."; 
        message.TextBody = "This is a test message. Please disregard.";
        message.Send(); 

        lblMessage.Text = "Message Sent";
    }

Imar · March 1st, 2011, 03:35 PM

Quote:

IMAR are you aware of this work around and issues?

Yes, I was aware of this. This is actually the "old" way of doing this. It works, but stufff in the System.Net namespace is designed to make all of this a lot simpler. I think with the proper configuration you should be able to do the same using managed code in .NET (E.g. the SmtpClient and MailMessage and so on).

Cheers,

Imar

Cooler · March 1st, 2011, 04:36 PM

Have tried everything.

The link in OP suggests that implicit SSL with port 465 will not work.
A known issue which doesnt seem to have been resolved in 4.0.....

'An alternate connection method is where an SSL session is established up front before any protocol commands are sent. This connection method is sometimes called SMTP/SSL, SMTP over SSL, or SMTPS and by default uses port 465. This alternate connection method using SSL is not currently supported.'