Introduction: SMTP Fun

This instructable is about hacking and just messing around with the SMTP servers in general. I will show you how to use nslookup to find out what your email's SMTP server is, how to telnet into it, and how to send mail from the server to yourself or other people.

note: FUBAR stands for something along the lines of "F***** Up Beyond All Recognition

Step 1: Getting the Names & Numbers

Ok, time for nslookup! Go to Start-->Run and type in: "cmd" and press enter. When the command prompt comes up, type in "nslookup", and then press enter. The command prompt should now have stuff written on the screen about your IP address, and about your ISP (Internet Service Provider). Now, type in:

set type=mx
(your email server here)

This should display your email provider's email servers.

Step 2: Finding the Right Address and Telneting In

From the last step, you can see a lot of different stuff that looks like gibberish to the untrained eye. But fear not, for I shall help you in this time of need! First, you only want to pay attention to the block of addresses at the top that are formated in a table. Bring up the command prompt, and type in:

telnet (first address here) 25

If you get a response from the server saying something like:

220 mx.google.com ESMTP 31si4851324nfu

Then you are all set up to go to Step 3: Mail Time! If not, and you get something like this instead:

Connecting to google.com.....Could not open connection to the host, on port 25: Connect failed

Then you need to repeat this step with the next server down the list. If you have exhausted your list from nslookup, and still had no luck, then there is probably a problem with your ISP or the people on that email service don't allow inbound telntet connections. For example, I have been told that AOL users can't telnet, but I can not test it because I don't have AOL.

Step 3: Mail Time!

As you can see in the pictures, I used these commands, in this order:
helo -- this preps the server for the mail address

mail from: -- This is who it sends from.

rcpt to: -- This is who it sends to.

data -- This tells it the following is the message

From:something here }
To:something here } These are some headers.
Subject:something else here }

(message here) -- this is the message

. -- this tells the server end of data, send it now.

exit -- exit the connection

As you can see in the pictures, pressing backspace does not work very well. :(