Is the LDAP service mandatory for analyzing whether an incoming traffic is a form of DHA attack?

Technically, LDAP service is not required. The DHA rule of IMSS relies on the result returned from Postfix, which in turn passes the result to FoxProxy, a sub-module of IP Profiler, for analysis. The LDAP server is just one of the many means by which Postfix checks for the existence of a recipient's mailbox.

$('#title').html($('meta[name=description]').attr('content'));

Is the LDAP service mandatory for analyzing whether an incoming traffic is a form of DHA attack?