by Ken Task.
Might have to do this via another workstation or find a way to install nmap on the server.
nmap -P0 FQDN_of_Moodle_Server
Is the default port for MySQL open/closed or?
Does config.php have 'localhost' for the DB server?
How does that resolve on the server itself? Check /etc/hosts file to see if
127.0.0.1 localhost
is there.
In the config file of Moodle try to use the IP address: 127.0.0.1.
$CFG->dbhost = '127.0.0.1';
No need to restart anything if changing config.php.
'spirit of sharing', Ken