Question

I’m building an app where the user creates an email and where the email is sent from his mail server. I’m not looking to receive any emails, just to send them. I need to access his mail server to do this and I’m wondering a) what kind of email servers are there (Exchange, SMTP, POP3…) and what kind of info does the user need to provide me (ie. what fields do I need in the DB).

If you know of any pitfalls to avoid, please let me know.

Thanks for your suggestions.

Answer 1

SMTP and POP3 are protocols, not Email Servers.

If I understand correctly, you need to connect to different email servers based upon the client that’s constructing the email to send the email through his/her mail server(?)

If that’s so, you need to, for every client of yours, find out their mail server’s IP address and the type of authentication, encryption, etc. that they support. Once you have that established, you need to connect to each server based with the specific credentials provided by your client and send the email through their SMTP server. Example:

// Create a message and set up the recipients.
MailMessage message = new MailMessage(
   "[e-mail]",
   "[e-mail]",
   "Quarterly data report.",
   "Hello, test email!.");


//Send the message.
SmtpClient client = new SmtpClient(server);
// Add credentials if the SMTP server requires them.
            // YOU NEED TO CHANGE THIS PART DEPENDING ON THE SPECIFICS OF THE
            //SMTP SERVER THAT YOU WILL BE USING
client.Credentials = CredentialCache.DefaultNetworkCredentials;

try {
  client.Send(message);
}
catch (Exception ex) {
  Console.WriteLine("Exception caught in CreateMessageWithAttachment(): {0}", 
        ex.ToString() );              
}

Above example was taken almost verbatim, from here.