Hello,
By default Zentyal will install a MySQL server without any root password during the Zarafa installation. In many scenarios, this may be very risky.
HowTo close this security hole:
1) Access to your Zentyal server CLI
2) Reconfigure your MySQL server using this command:
sudo dpkg-reconfigure mysql-server-5.1
3) Enter the root password when prompted to do so
Et voilĂ !
Best,
Marcus