Simple Mail Transfer Protocol

This protocol is used for sending mails to a mailserver. The default port number for SMTP is 25. If you are doing a TCP/IP Socket Program, connect it to port number 25. Then it follows the sequence as below,

S: Sending from Client R: Received to the Client

On connecting .,
     R: 220 md3.vsnl.net.in ESMTP Sendmail 8.8.8/8.8.8; Fri, 25 Jun 1999 08:00:41 GMT
    S: HELO nkans.com
    R: 250 md3.vsnl.net.in Hello [202.54.71.66], pleased to meet you
    S: MAIL FROM: <sender@domain1.com>
    R: 250 <sender@domain1.com>... Sender ok
    S: RCPT TO: <recipient@yahoo.com>
    R: 250 <recipient@yahoo.com>... Recipient ok
    S: DATA
    R: 354 Enter mail, end with "." on a line by itself
    S:   send the data according to mime spec if you need attachments
    S:   .
    R: 250 IAA26087 Message accepted for delivery
    S:   QUIT

The raw commands to handle SMTP server were

              HELO hostname
              MAIL FROM: sendermail address
              RCPT TO: receipient address
              DATA
              QUIT

Do you need implementation in C / VC++ / Java.

Need more information on RFC Contact : http://ds.internic.net

Like to know also about POP3 Server.