Aliasdetourhost_null_optin MTA option
User/group LDAP attribute validity and interpretation options:
(New in MS 6.2p4.) Normally, the simple presence of a detour optin attribute (the attribute named by the
ldap_detourhost_optin MTA option in a user entry, or new in 7.0.5, the attribute named by the
ldap_domain_attr_detourhostoptin MTA option in a domain entry) suffices to cause message detour for messages coming in a channel marked
aliasoptindetourhost; the value of the attribute is irrelevant. However, some directory maintenance and provisioning tools cannot easily delete or omit an attribute; instead, they always provide the attribute but assume that some "off" or "null" value for the attribute is available. The
aliasdetourhost_null_optin option allows for better interaction with such directory tools. It specifies what value the detour optin attribute (that attribute named by the
ldap_detourhost_optin MTA option, or new in 7.0.5 the
ldap_domain_attr_detourhostoptin MTA option) must have in order to be ignored (for the MTA to act as if the attribute was not present at all in the user or domain entry). The default value for this option is the empty string, when means that by default a present but empty detour optin attribute is ignored.
Note that message detouring of the
aliasoptindetourhost type is typically a detour to some third-party host or channel performing spam/virus filtering. Thus the value of
aliasdetourhost_null_optin typically means what value to be considered as the "this user hasn't asked to do spam/virus filtering" value. But note that, for instance, use of such a null value in a user entry does not necessarily disable the detouring (the spam/virus filtering); a user who is not opted-in personally may still be detoured due to a domain level setting, or a channel level (
aliasdetourhost channel option) setting.