This is one the first hax0r-y tricks I learned, back in the heyday
s of my youth
(about 3 years ago). It's kind of a lame trick and all, but it's fun once or twice.
1. Connect to the Internet. (if that step wasn't obvious...)
2. Telnet to port 25 of the server you intend to spoof from. That should look something like this (from a Un*x or DOS command prompt):
telnet xxx.xxx.com 25
Port 25 is the SMTP
port. It sends outgoing emails.
Many servers won't let you spoof emails (because it's a hax0r-y trick). The only server I have found to work is that of my ISP - ecn.ab.ca
However, find your own damn server if you plan to do much of this. Anything overused tends to not last long
3. Type 'mail from:firstname.lastname@example.org' (excluding the quotes and replacing name and server with the name and server you want, of course)
4. Type 'rcpt to:email@example.com' (replacing this placeholder address with the address of the person you want to send mail to, of course)
5. Type 'data'
6. Type your message. When you are done, type a single '.' (period) on a line by itself
7. Exit telnet.
An important thing to note is that you may not be able to use backspace, so type the sender's address, the recipient's address and the message properly the first time.
These are the only steps necessary to spoof email from the server I have listed above. They may be different on other servers - ie. some servers require you to login before sending email.
Also, many servers have implemented help - just type 'help' or 'help commandname' to get more information on the server or the command.