INLS 181 Lab: Clients

I Am the Client

Is there a difference in the headers of the the "normal" e-mail client and the ruby messages?

The first difference apparent is that there is a To: line and a Subject: line in the Mulberry message that is absent in the ruby message. The second difference is that in the ruby message, after the Message-ID, there is an "X-Authentication Warning" that states that the server did not use HELO protocol. In the Mulberry-sent message, there are 5 lines with details such as the mailer and the content type.

How do you suppose that difference arose?

There must be more to what the e-mail client does that what I did to send a message using ruby. From the "X-Authentication Warning," it looks like there is a specific protocol (HELO) used by e-mail clients that specifies information about the message content.

With a Twist

Is the message delivered? Who does it appear to be from?

The message is delivered. It appears to be from supergirl@xtc.com

Take a look at the e-mail headers. Who is actually listed in the "From:" line?

There are three lines detailing who the e-mail is from:

Received: from email.unc.edu (mgate11.isis.unc.edu [152.2.1.118])

Received: from smtp.unc.edu (smtpsrv12.isis.unc.edu [152.2.1.243])

Received: from ils-pc28.ils.unc.edu (ils-pc28.ils.unc.edu [152.2.81.128])

Is there enough information in the header to determine who actually sent the mail?

The third line tells you from which computer the message was sent. If the person had logged on to the computer using their own login, you would be able to tell who was using the computer at the time the message was sent (assuming you had that kind of authority). I would also surmise that the sender had a UNC e-mail account given that the first line is from email.unc.edu

A Leading Example

What message did you get?

I got the html version of the main class webpage and then "Connection closed."

Where do you think the message came from?

The text of the webpage came from Kristin Chaffin's 181 folder on ruby.

"Who" gave it to you?

I suppose you would say that ruby gave me the file.

What protocol were you speaking?

I was "speaking" file transfer protocol.

What are the numbers at the end of the telnet commands? What do they mean? What do they specify? What do they tell the computer to do?

The 80 at the end of the command specifies the server to connect to when executing the command. 80 is the port used to specify the web server so that you are telnetting to that server rather than the SMTP or FTP server.