User accounts can be shared among all sites running on one Kentico instance. This means that if users create accounts on one site, they can automatically sign in to other sites running on the same instance using the same credentials.
This behavior can be switched on or off in Settings -> Membership & Security, using the Share user accounts on all sites check box.
- If the check box is selected, user accounts created on one site are shared among all the sites running on the instance.
- If the check box is cleared, the system only assigns new accounts to the current site and not the others.
However, registration web parts have the Assign to sites property. Using this property, you can determine which sites the user accounts created via the web part are assigned to.
User name prefixes and shared accounts
If your instance has the Use site prefixes for user names setting enabled (can also be configured in Settings -> Security & Membership), avoid shared user accounts. Prefixes allow the creation of users with names that are not globally unique, and always bind each user to a specific site.
If the Share user accounts on all sites setting is enabled or you manually assign users to multiple sites (for example when editing users in the Users application on the Sites tab), you may encounter incorrect behavior or problems with multiple identical users names on a single site.