[Dovecot] LDAP.conf filter issue

All,

We are trying to use the user_filter options to limit authentication to a single user group. The cusotmer has security rules that they want to only have users belonging to a group to have access. Sample we have tried.

auth_bind = yes

auth_bind_userdn = EXAMPLE\%n

base = /

hosts = example.test.com

ldap_version = 3

user_filter = (&(sAMAccountName=)(memberOf=CN=LR3BCC-DL,OU=Autonomy,OU=Exchange,OU=Enterprise Administration,DC=example,DC=test,DC=com)) Thanks Tony