Install iRedMail

Check ldap connection

ldapsearch -x -h ad.example.com -D 'vmail' -W -b 'cn=users,dc=example,dc=com'

Flush unwanted parameters

postconf -e virtual_alias_maps=''
postconf -e sender_bcc_maps=''
postconf -e recipient_bcc_maps=''
postconf -e relay_domains=''
postconf -e relay_recipient_maps=''
postconf -e sender_dependent_relayhost_maps=''

Set mail domain

postconf -e smtpd_sasl_local_domain='example.com'
postconf -e virtual_mailbox_domains='example.com'

Set transport file

postconf -e transport_maps='hash:/etc/postfix/transport'

Set maps

postconf -e smtpd_sender_login_maps='proxy:ldap:/etc/postfix/ad_sender_login_maps.cf'
postconf -e virtual_mailbox_maps='proxy:ldap:/etc/postfix/ad_virtual_mailbox_maps.cf'
postconf -e virtual_alias_maps='proxy:ldap:/etc/postfix/ad_virtual_group_maps.cf'

Create the transport file /etc/postfix/transport

Hash postfix transport

postmap hash:/etc/postfix/transport

Check user mailbox

postmap -q user@example.com ldap:/etc/postfix/ad_virtual_mailbox_maps.cf

Check user account

postmap -q user@example.com ldap:/etc/postfix/ad_sender_login_maps.cf

Check groups of mailing

postmap -q testgroup@example.com ldap:/etc/postfix/ad_virtual_group_maps.cf