I have to remove or blacklist an LDAP/dovecot user. The authentication is setup from active directory what I cannot manage so I thought there should be a way at least to disable this specific user on the mailserver locally.

# Virtual Accoutns - LDAP - MS AD
virtual_mailbox_maps = ldap:/etc/postfix/ldap_mailbox_maps.cf
virtual_alias_maps = ldap:/etc/postfix/ldap_alias_maps_redirect_true.cf ldap:/etc/postfix/ldap_alias_maps_redirect_false.cf ldap:/etc/postfix/ldap_mailbox
_groups.cf
virtual_mailbox_domains = domain.com
virtual_uid_maps = static:1000
virtual_gid_maps = static:1000
virtual_transport = dovecot
dovecot_destination_recipient_limit = 1

Anybody knows how to do it?

I followed this guide for disabling 1 user through postfixes access file:

http://www.cyberciti.biz/faq/howto-blacklist-reject-sender-email-address/

Unfortunately it doesn't work. It's like the settings stored in LDAP are overruling the access rule. Instead of postfix rejecting the mail it keeps accepting it. Thanks!