Open iim.conf.
See iim.conf File Syntax for instructions on locating and modifying iim.conf.
Specify the attribute you want to use for user IDs as the value for iim_ldap.user.uidattr.
The default value is uid.
For example, to use the loginname attribute, set the iim_ldap.user.uidattr attribute as follows:
iim_ldap.user.uidattr=loginname
Save and close the file.
Add the index directive to the indexing rules in LDAP:
index loginname eq