I recently worked on a Barracuda / Lotus environment.  Below is what you need to know to get Barracuda LDAP authentication going against the Lotus environment: Lotus Domino receiving messages for one domain: LDAP username: username@domain.com LDAP filter: (|(mail=${recipient_email})(cn=${recipient_local_part})(shortname=${recipient_local_part})(fullname=${recipient_local_part})) Lotus Domino receiving messages for two domains: If your Lotus Domino server receives messages for two domains, Read more [...]