If you are wanting to use Zimbra and SpamTitan together , this is a suggested configuration to get Zimbra and SpamTitan to work together.
Zimbra Support does not support the SpamTitan product. You will need to contact the support team at SpamTitan.
SpamTitan Setup - Step One
Domain: example.com Destination Server: <Zimbra IP Address> or <Zimbra Hostname> Destination Port: 25
SpamTitan Setup - Step Two
Recipient Verification: LDAP Recipient Verification LDAP Server: <Zimbra IP Address> or <Zimbra Hostname> LDAP Port: 389 LDAP Search User DN: uid=zmpostfix,cn=appaccts,cn=zimbra LDAP PASSWORD: ************ LDAP Query Filter: (&(|(zimbraMailDeliveryAddress=%s)(zimbraMailAlias=%s)(zimbraMailCatchAllAddress=%s))(zimbraMailStatus=enabled)) LDAP Result Attribute: zimbraId
Note: If you are unsure of zimbra's zmpostfix password, run the following as the zimbra user from the zimbra-MTA node.
zmlocalconfig -s ldap_postfix_password ldap_postfix_password = u5k1nfJ6 <<=== Should see something like this
According to SpamTitan Support, SpamTitan product just needs the "zimbraId" result attribute as the ldap query should only return one entry for a valid address, on return one for every valid address.