1.6 Other suggested enhancements

For users who have professional requirements such as system administrators for office environments and Internet Service Providers you may want to consider adding the mrbl patch to your configuration. This patch adds the capability to use multiple rbl entries (Real Time Black-hole Lists) to your base level configuration. Details on how to get and install this patch will be covered in section 2.3.1 of this document. By default, sendmail allows you to configure one rbl entry.