Java Reference
In-Depth Information
students. (Of course, the author of this topic had absolutely nothing to do with such
despicable behavior. ;-) ) The interaction with the SMTP server went something like
this; input the user types is shown in bold (the names have been changed to protect the
gullible):
flare%
telnet localhost 25
Trying 127.0.0.1 ...
Connected to localhost.sunspot.noao.edu.
Escape character is '^]'.
220 flare.sunspot.noao.edu Sendmail 4.1/SMI-4.1 ready at
Fri, 5 Jul 93 13:13:01 MDT
HELO sunspot.noao.edu
250 flare.sunspot.noao.edu Hello localhost [127.0.0.1], pleased to meet you
MAIL FROM: bart
250 bart... Sender ok
RCPT TO: local@sunspot.noao.edu
250 local@sunspot.noao.edu... Recipient ok
DATA
354 Enter mail, end with "." on a line by itself
In a pitiful attempt to reingratiate myself with the students
after their inevitable defeat of the staff on the volleyball
court at 4:00 P.M., July 24, I will be throwing a victory
party for the students at my house that evening at 7:00.
Everyone is invited.
Beer and Ben-Gay will be provided so the staff may drown
their sorrows and assuage their aching muscles after their
public humiliation.
Sincerely,
Bart
.
250 Mail accepted
QUIT
221 flare.sunspot.noao.edu delivering mail
Connection closed by foreign host.
Several members of the staff asked Bart why he, a staff member, was throwing a victory
party for the students. The moral of this story is that you should never trust email,
especially patently ridiculous email like this, without independent verification.
In the 20 years since this happened, most SMTP servers have added a little more security
than shown here. They tend to require usernames and passwords, and only accept con‐
nections from clients in the local networks and other trusted mail servers. However, it's
still the case that you can use Telnet to simulate a client, see how the client and the server
interact, and thus learn what your Java program needs to do. Although this session
doesn't demonstrate all the features of the SMTP protocol, it's sufficient to enable you
to deduce how a simple email client talks to a server.
