The excellent description on secure multi-site Drupal installation by Justin Hileman worked like a charm. However, for my own records, it’s a good idea to save the exact procedure that I used on my Centos 5.3 system. Hopefully it might help someone else who wants a complete rundown. So, if you dare to unleash another hydra-headed monster on your website, here you go, Nick! Scenario: using one database instance, I wanted to run multiple Drupal sites by using the same core modules and the same contributed modules. The plan was to first install Drupal core, and then to use CVS to get contributed modules, allowing for fairly simple CVS updates of new contributed modules. (Of course, you could do the same to obtain Drupal core, if you want.) Each Drupal site would live in its own folder below the webroot, while the actual core installation and multisites existed above the webroot in an area secure from casual intruders.