Send an e-mail

• Generating an e-mail is an incredibly easy thing to do, and we can do it with the knowledge we already have.
• Spoofing a From address is also very easy.  Unfortunately, this has lead to a lock down on many servers, so that you can't just connect and send an e-mail from anyone.
• In the old days, you could just dummy up an e-mail to anyone on any server.  Not so now.  As a matter of fact, I am writing and testing this from home with the expectation that it will not work on oz.  In class, we'll try it from oz and we'll jus see if it works.  I am going to try it on one.net and zoomtown, my ISP at home.  Unfortuantely, at this time Zoomtown is down and I can't test it.  :(
• Now, the details of sending an e-mail:
• E-mails are sent on port 25.  Connect to the server as you normally would, just specify 25.  This is considered the SMTP, or Simple Mail Transport Protocol, port.
• Most Unix servers use sendmail for SMTP.  If you've ever written a Perl script that sends an e-mail, it probably uses sendmail.  The e-mails we generated in 30-IT-252 used sendmail on oz.
• After you've opened a socket, send you need to send data to sendmail.  Here's an example of me sending an e-mail to myself:

HELO
MAIL FROM: <jonesbr@email.uc.edu>
RCPT TO: <UCInternet2@yahoo.com>
DATA
Hello, I am sending this from Java.
See you later,
Brandan
QUIT
• We'll write a program similar to the one on page 211 in the book, including the threads.

Created by:  Brandan Jones December 17, 2001