The AD has an unsatisfactory performance. However, by coincidence or not, the users/groups that will use the IPBrick services are all located in a specific OU (Organizational Unit) of the AD (and/or sub-OUs of this specific OU).
Eg: ou=myfavoritefolder,dc=domain,dc=com
In IPBrick, in the parameterization of the authentication mode we can change the values for connecting to the AD.
Note: By default it is recommended that the DN of the groups search and the DN of the users' search is identical to the base DN (top), because neither of them are always in the same OU and thus, working in all cases.
However, in some situations, like this one in scenario B, we find that making the following changes increases the AD's (IPBrick) performance:
ou=myfavoritefolder,dc=domain,dc=com
ou=myfavoritefolder,dc=domain,dc=com