Very different with POP3, SMTP is send email protocol. Default port listening in 25.
Begin session, SMTP client establish TCP connection to server. Server reply message information
- Using SMTP
EHLO <domain of client> ( or HELO)
Used to identify the SMTP client to the SMTP server. If server supported, it reply "250….."
MAIL FROM: <sender-address>
RCPT TO: <receiver-address>
If there are many receiver. Client has to send many time
Content of email.
Symbol ending content is "<CRLF>.<CRLF>"
Reject mail sending
Close session. Server will send mail when client close session.
write by : hotdream1990