[Mimedefang] OT: How to keep sendmail from using /etc/passwd

[David Nelson]

I know this question is better for a sendmail user group, but hopefully
it's a quick and easy answer.

I need to know if there's a way to tell sendmail to not consider using
/etc/passwd for the LHS and to strictly rely on aliases and
virtusertable.  I have e-mail addresses like mike at somedomain.com, but
the username in /etc/passwd is mblack.  The problem is that
mblack at somedomain.com works as a valid address.

Any ideas?

Thanks!
-- Dave