Beginning with V8.12
sendmail, it is possible to screen email based
on sender and recipient address pairs stored in the
access database. One use for such a method might
be to prevent one employee from receiving mail from another employee.
Another use might be to prevent a pseudo-user, such as
admin, from receiving spurious reports from
another user, such as bin. Yet another use might
be to reject spam mail to a mailing list.
This compat_check feature is described in full in