Trouvé ici :
http://www.webhostgear.com/43.html
1. Login to your server and su to root, I know the irony!
2. cd /root
3. pico .bashrc
4. Scroll to the end of the file then add the following:
echo ‘Accès Shell Root le ‘ `date` `who` | mail -s `hostname` Shell Root de `who | cut -d »( » -f2 | cut -d ») » -f1`
you@yourdomain.com
Replace YourServerName with the handle for your actual server
Replace you@yourdomain.com with your actual email address
5. Crtl + X then Y
Now logout of SSH, close the connection and log back in! You should receive an email address of the root login alert a few minutes afterwards.