The telnet protocol (Telecommunication network) was invented in 1969 as a command line interface to connect to remote computers either on the Internet or Local Area Networks.
You can access telnet in Windows XP by clicking on the Start button, clicking Run, typing cmd and pressing enter. The black command console will open. At the prompt, type telnet.
On Windows Vista it is turned off by default. To turn on telnet, click Start, then open Control Panel. Look for Programs and Features and open it.

On the right of this window, click on Turn Windows features on or off.

In the new window, scroll down to Telnet Client and Telnet Server and select both of them.

Click OK then close the Control Panel window. Press the Windows button on the keyboard to open the Windows Menu, and type cmd, then press enter. Type telnet as the command prompt.
At the telnet prompt, you can type ?/help for some basic commands.
Fun with Telnet.
If you have the telnet prompt open press q to quit to the command prompt. Type the following:telnet towel.blinkenlights.nl
press enter and watch an ASCII art classic movie. Enjoy!
Another trick is to access SMTP (Simple Mail Transfer Protocol) mail servers of various mail providers. You can send mail directly from the server, possibly form anyone's account. Type the following:
telnet mail.hotmail.com 25
You'll connect to hotmail.com and receive a warning about sending spam.
helo
This will basically say hello to the server, you may use your computer name to identify yourself to some servers.
mail from:
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
This is who the mail sender is. Choose any email you want.
rcpt to:
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
This is who you will be sending the email to.
data
This turns on the data you will be sending.
your data gets inserted here and you
can type it on as many lines as you want
.
This means you have finished the data.
quit
This closes the connection

Check your email account for some mail. If this doesn't work on hotmail for you, try another companies SMPT. Above is an example from my ISP's email account. You need to use port 25, but some ISP's block this by default.
There is a list of available BBS's at http://synchro.net/sbbslist.html








