Can I send emails without authenticating on the SMTP server?

Question

I am creating simple email sending application. In my application when ever I send email I have to put my email address or password as from but I don't want to use password only want to put email.

So:

Can I send email without using password using C#/.net application?

This is my code:

try
{
    // setup mail message
    MailMessage message = new MailMessage();
    message.From = new MailAddress(textBox1.Text);
    message.To.Add(new MailAddress(textBox2.Text));
    message.Subject = textBox3.Text;
    message.Body = richTextBox1.Text;

    // setup mail client
    SmtpClient mailClient = new SmtpClient("smtp.gmail.com");
    mailClient.Credentials = new NetworkCredential(textBox1.Text,"password");

    // send message
    mailClient.Send(message);

    MessageBox.Show("Sent");
}
catch(Exception)
{
    MessageBox.Show("Error");
}

Answer 1

Can i send Email without using password using c#/.net application ?

Yes, if you have access to an email gateway that doesn't require authentication you can simply do:

SmtpClient mailClient = new SmtpClient("your.emailgateway.com");
mailClient.Send(message);

Maybe your company or ISP can provide one for you?