SMTP

import smtplib
server = smtplib.SMTP('localhost', 25)
server.sendmail('from@example.com', 'to@example.com', 'Test')
server.quit()

telnet mail.example.com 25
HELO example.com
MAIL FROM:<sender@example.com>
RCPT TO:<recipient@example.com>
DATA
Subject: Test
Test message
.
QUIT