Hello,
I am testing the Dovecot mail server with the iRedMail configuration. My backend is based on LDAP. I would like to set up the "Public" folders in such a way as to grant permissions to specific groups of users.

To achieve this, I created the following entry in the configuration:
acl = vfile:/etc/dovecot/dovecot-acl-global:cache_secs=300

For individual users, the global permissions work correctly, and I achieve what I want. However, I am unsure how to grant permissions for a group. Specifically, I know that I should include permissions for groups in this file, for example:

Public/ anyone l
Public/IT_Suwalki group=grupa1 lrwstipek
Public/IT_Suwalki/* group=grupa1 lrwstipekxa

But I don't know how to associate users with groups. From what I managed to figure out, the user should have the "ACL_GROUPS=grupa1,grupa2" variable, and it should be passed by the postlogin script. But how can I do that? Do you have any working example of such a script?

Which LDAP attributes should this script utilize? In my LDAP, there is an attribute called "memberOfGroup"; can I use it?