query-based distribution group

A distribution group that uses a Lightweight Directory Access Protocol (LDAP) query to derive its membership at the time the message is sent. For example, a query-based distribution group might specify an LDAP query such as "Users homed on Exchange server X." When someone sends a message to this query-based distribution group, Exchange executes the associated LDAP query against Active Directory directory service, returns a list of all users currently homed on Exchange server X, and sends the message to that list of users. [Exchange 2003]