Sending a simple mail from debian slug

["Tobias Wagner" <tw.castell@arcor.de>]

Hello,

I am trying to send a simple email to my address with no success. I logged  
in via ssh and typed:
 echo "This is a test." | mail -s "Test subject" test@gmx.de

It didn't give an error message, but no email was received.

I have searched the net but there's so many tools associated to it (mutt,  
exim, sendmail, ...) that I am totally confused. I only need to send mails  
from commandline, no inbox needed.

Any help would be great.

Tobias.

P.S.: I have a NSLU2 with debian as described at cyrius.com.