In a clustered environment, specifying a Port number in your extension site.ini [DatabaseSettings] causes eZ Publish to use the database settings in file.ini.append.php for all database queries.

Interestingly, there is no documentation on this setting - is it deprecated?

Steps to reproduce

1. Clusterize your installation/site (refer to docs)
2. In your front-end extension siteaccess site.ini, specify Port=3306 (if using mysql) under [DatabaseSettings]
3. View your front-end siteaccess via the web