1. How does a simple protocol like the email protocol SMTP work 1. Open telnet connection Do remote login to the system you want to send email to Note: You probably will have to telnet to your AFS account first And then from there telnet to a mail server as described in the following. Once connected to your account (such as to gould.njit.edu) you can then: telnet gould.njit.edu 25

2. make it echo what you type Use the command prompt to initiate telnet or a GUI telnet tool Like the following:

3. 2. This is the remote system 3. This is the port that email server listens om 4. Select this type of terminal option [VT100 option may also work] 5. click connect to logon

4. 7. This is response from the mail server on cis.njit.edu [ cis is an alias for homer] 8. 220 is a code --- means everything is OK so far time/date

5. 9. This is what I type in as my part of the dialog I am saying HELO to the mail server on that system on port 25 10. The system responds with an Acknowledgement

6. 11. I then identify who I am - this is not verified & could be spoofed I am saying MAIL FROM: followed by my email address in 12. system says my address is OK

7. 13. I then identify who I am sending email to on the server - in this case I just sent the mail to myself I say: RCPT TO: followed by email address I am contacting 14. the mail server acknowledges the target email address is on its server

8. 15. I got error message from server because I backspaced then I re-entered command to indicate I am about to send the data or contents of the email the server was satisfied & said I can enter the email - terminating the message with a Period. 16. I entered the message here & ended with period 17. server accepted the email 18. I then typed QUIT [not shown] to end session