Just to start off, Joomla does work with remote database connections.
I am going to put what I posted earlier in a better format.
To connect a Joomla site to a remote database, (not on your host account) you will need to make changes to the following in the configuration.php file in Joomla. You will also need to give the remote database the ip address of the server you will connect with.
This is what needs changing in the Joomla configuration.php file to connect to the new database:
$mosConfig_db = 'remote_database_name';
$mosConfig_host = 'remote_database_host';
$mosConfig_password = 'remote_db_usr_password';
$mosConfig_user = 'remote_db_usr_name';
The config line $mosConfig_host = 'remote_database_host'; is the db host you want to connect to (normally localhost) and in this case a remote db host. In my case 'athena.medialayer.net' is the remote db host I connect to for a remote database connection. Put the remote server in without the http://
. In a normal Joomla install this would be localhost, but your trying to connect to a remote database so you have to put in the server name the remote database lives on.
If you can't figure out the proper server name, then ask your hosts tech support for the name of the server your needing the information for. You may also need the mysql port number but try connecting without the number first. Standard mysql port number is 3306, but hosts can change it. Your host may also have a FAQ or help file explaining how to connect to a database remotely.
You will still need to set up the remote database (the one you want to connect to) properly to enable a connection from an remote ip address.
Log in to your desired remote domain (where the database is you want to connect to) and go to the mysql management area.
Set up a new user and password in the desired database. This is the one you will use along with the database name and the mysql server name in Joomla to remote connect to this database.
Scroll down the page below where the users are listed and you should find Access Hosts (or remote database connection). Enter the ip address of the server you want to connect from here. This should be a static ip address for best results and could be the domain ip of a clients server like in the first posters question.
If your looking to change the servers my.cnf file to setup remote access, then this is beyond the scope of this forum and I would suggest you look on a mysql forum for help.