I found this in the release notes of SME 6.0:
The mysql database daemon is configured by default to accept only
local connections (i.e. it is not accessible via the network).
This is a security precaution. We only use mysql for webmail
preferences, and only require access from localhost.
If you wish to enable local network access, you can do so via:
/sbin/e-smith/config setprop mysqld LocalNetworkingOnly no
/sbin/e-smith/expand-template /etc/my.cnf
/etc/rc.d/init.d/mysqld restart