Hi,
I have some drupal7 sites: site1, site2, site3, etc.
Really I'm speaking of a multi-instance configuration of Drupal ( the code is the same, but each instance has an its own database).
These sites are already in production and already have their own users.
Now I'd like that a user can pass from a site to another logging only once.
How can I face this problem?
Should I have an authentication server?
Should I have all the users on all the Drupal instances?
Thank you very much for your advice.
claudio