Joomla 1.5 has a simple, but in many cases, effective access control list. But if you need more access levels and greater control over what can be managed, you need to revert to a third party extension. This and the limitations of the section/category feature were the most criticised features of the "old" Joomla. This all changed with Joomla 1.6 with the introduction of a very flexible ACL. But did it go too far? This complexity has meant that it can be confusing to setup and manage.
Perhaps the greatest challenge with the ACL is understanding inheritance as introduced in last week's topic Joomla ACL Actions explained. Permissions settings flow through at two levels; the Joomla hierarchy and the group hierarchy. For example, allowing a certain action within Global Configuration means that action will also be allowed at the category level and article level. However you can then override the setting at the other levels if you wish. Similarly, if you apply a permission to a group, any sub-groups will inherit that setting, but can be overridden.
If you are building a site from scratch, or if your ACL rules are simple, it easy to keep on top of things. But if you have a complex site, multiple groups and users or if you have taken over the management of a site, the flexibility of the ACL can be a headache. ACL Manager is the ideal troubleshooting companion because it displays the current permissions settings for either groups or individual users. If a particular user or group of users can't access something, you can view the current settings within a grid to help determine which setting is incorrect.
If an incorrect setting or conflict is detected, it's easy to find the correct location to fix it as each "asset" is linked to its corresponding permissions window. Once everything is correct, use the print mode to keep a permanent copy as a quick reference later.
The latest version also includes a diagnostic feature that can discover problems with the assets table in the database. These issues can be the cause of permissions problems and so if found, ACL Manager can correct the entries.
If your site uses the Joomla ACL and it's in any way confusing, you'll find this to be a must-have tool. ACL Manager is a commercial extension that is available for 10 euro including support and updates for 6 months. A 12 month subscription is €17.50.