LDAP Authentication Redmine

Login into redmine website and Administration -> LDAP authenication -> New authenication mode

Name: <your ldap server name>
Host: <ldap server ip>
Port: 389 LDAP
Account: cn=admin,dc=example,dc=com
Password: <your ldap password>
Base DN: ou=Users,dc=poc2018,dc=com
LDAP filter: (&(objectClass=posixAccount)(memberOf=cn=redmine,ou=Groups,dc=example,dc=com))
Timeout: 25
On-the-fly user creation: checked/Yes
Attributes
Login attribute: cn
Firstname attribute: givenName
Lastname attribute: sn
Email attribute: mail

Must support memberOf, otherwise all your ldap user can login into your redmine. You may find other ways to limit your users by using other attributes but its not indexed and its harder to manage as the fields is buried in each user.

Go to Administration -> Users -> New user

1. Change Authenication mode to the <ldap server name>
2. click on Login and begin to type user's cn, it has fuzzy search so you can select from result
3. All necessary fields will autocomplete and you can modify other attributes.  Please note do not grant to many Administrators in redmine.