C# Send Email via SMTP

Simple Mail Transfer Protocol (SMTP)

Simple Mail Transfer Protocol (SMTP) is a TCP/IP protocol used in sending and receiving e-mail. Most of the e-mail systems that send mail over the Internet use SMTP to send messages from one server to another. The messages can then be retrieved with an e-mail client using either POP or IMAP.

SMTP Class in C#:  MailMessage class is part of the namespace System.Net.Mail and it is used to create the email messages that are sent to the SMTP Server. The delivery of the message will be taken care by the SmtpClient Class.

SMTP Class Properties:

• Host: Server URL for SMTP
• EnableSsl: True or False.
• Port: Port Number of the SMTP server
• Credentials: Valid login credentials for the SMTP server (the email address and password).
• UseDefaultCredentials: When we set to True then that specifies to allow authentication based on the credentials of the account used to send emails.

Below are the list of few SMTP Server and Port Number details.

S.No	Mail Server	SMTP Server( Host )	Port Number	SSL
1	Gmail	smtp.gmail.com	587	YES
2	Outlook	smtp.live.com	587	YES
3	Office365.com	smtp.office365.com	587	YES
4	Zoho Mail	smtp.zoho.com	587	YES
5	Mandril	smtp.mandrillapp.com	587	YES
6	SendGrid	Smtp.sendgrid.net	587	YES

Sending an HTML email in C#

Sample project is available at this Github location

using System.Net;
using System.Net.Mail;

var to = new MailAddress("fromaddress@example.com");
var from = new MailAddress("toaddress@example.com");

var message = new MailMessage(from, to);
message.Subject = "Test Email Subject";
message.Body = "<h1> Test Email Message</h1>";
message.IsBodyHtml = true;
SmtpClient client = new SmtpClient("smtp.gmail.com", 587)
{
Credentials = new NetworkCredential("smtp_username","smtp_password"),
EnableSsl = true
};

try
{  
client.Send(message);
}
catch (SmtpException ex)
{
Console.WriteLine(ex.ToString());

}